Effect of parity on second-trimester uterine artery Doppler flow velocity and waveforms

[Factors influencing the occurrence of small for gestational age at different degrees]

OBJECTIVES

To investigate the factors influencing the occurrence of small for gestational age (SGA) at different degrees and provide a basis for early identification of severe SGA cases.

METHODS

Neonatal and maternal prenatal information were retrospectively collected from January 2018 to December 2022 at Peking University People's Hospital. The neonates were divided into three groups: severe SGA group (birth weight below the 3rd percentile for gestational age and sex), mild SGA group (birth weight ≥3rd percentile and <10th percentile), and non-SGA group (birth weight ≥10th percentile). An ordered multinomial logistic regression model was used to analyze the factors influencing the occurrence of SGA at different degrees.

RESULTS

A total of 14 821 neonates were included, including 258 cases (1.74%) in the severe SGA group, 902 cases (6.09%) in the mild SGA group, and 13 661 cases (92.17%) in the non-SGA group. The proportions of preterm births and stillbirths were higher in the severe SGA group compared to the mild SGA and non-SGA groups (P<0.0125). The proportion of neonatal asphyxia was higher in both the severe SGA and mild SGA groups compared to the non-SGA group (P<0.0125). Ordered multinomial logistic regression analysis showed that maternal pre-pregnancy underweight (OR=1.838), maternal pre-pregnancy obesity (OR=3.024), in vitro fertilization-embryo transfer (OR=2.649), preeclampsia (OR=1.743), connective tissue disease during pregnancy (OR=1.795), nuchal cord (OR=1.213), oligohydramnios (OR=1.848), and intrauterine growth restriction (OR=27.691) were all associated with a higher risk of severe SGA (P<0.05). Maternal parity as a multipara (OR=0.457) was associated with a lower likelihood of severe SGA (P<0.05).

CONCLUSIONS

Maternal pre-pregnancy underweight, maternal pre-pregnancy obesity, in vitro fertilization-embryo transfer, preeclampsia, connective tissue disease during pregnancy, oligohydramnios, nuchal cord, and intrauterine growth restriction are closely related to the occurrence of more severe SGA. Maternal parity as a multipara acts as a protective factor against the occurrence of severe SGA.

The Risk of Perinatal Mortality in Nulliparous Women Compared to Primiparous Women at Term

OBJECTIVE

 The aim of this study was to determine the rate of perinatal mortality among nulliparous women compared with primiparous women at term and further characterize the risk of stillbirth by each week of gestation.

STUDY DESIGN

 This is a retrospective cohort study of all term, singleton, nonanomalous births comparing perinatal mortality (stillbirth and neonatal death [NND]) between primiparous (parity = 1, with no history of abortion) and nulliparous (parity = 0) women who delivered in California between 2007 and 2011. Chi-squared tests and multivariable logistic regression analyses were performed to determine the frequencies and strength of association of perinatal mortality with parity, adjusting for maternal age, race, body mass index, pregestational diabetes, chronic hypertension, fetal sex, smoking status, and socioeconomic status. The risk of stillbirth at each gestational age at term was calculated using a pregnancies-at-risk life table method. A p-value less than 0.05 was used to indicate statistical significance.

RESULTS

 Of 1,317,761 total deliveries, 765,995 (58.1%) were to nulliparous women and 551,766 (41.9%) were to primiparous women with one prior birth. Nulliparous women had increased odds of stillbirth (adjusted odds ratio [aOR], 3.30; 95% confidence interval [CI], 2.93-3.72) and NND (aOR, 1.54; 95% CI, 1.19-1.98) compared with primiparous women. The risk of stillbirth in nulliparous women was greater at every gestational age between 370/7 and 410/7 weeks compared with primiparous women. Nulliparous women also had increased odds of small for gestational age infants at less than 10% birth weight (aOR, 1.76; 95% CI, 1.72-1.79), less than 5% birth weight (aOR, 1.91; 95% CI, 1.86-1.98), and less than 3% birth weight (aOR, 2.02; 95% CI, 1.93-2.11).

CONCLUSION

 Perinatal mortality is significantly greater in nulliparous women compared with primiparous women with term deliveries. These findings suggest that low-risk nulliparous women may require increased surveillance. There may be a role in improving maternal health by maximizing physiologic adaptation in nulliparous women.

KEY POINTS

· Parity is associated with perinatal mortality.. · Perinatal mortality is significantly greater in nulliparous women compared with primiparous women.. · The risk of stillbirth in nulliparous women is greater at every gestational age compared with primiparous women..

Understanding trimester-specific miscarriage risk in Indian women: insights from the calendar data of National Family Health Survey (NFHS-5) 2019-21

BACKGROUND

The primary public health issue, especially in low- and middle-income countries, is early pregnancy loss driven by miscarriage. Understanding early pregnancy losses and the characteristics of mothers who have miscarriages is essential to creating effective reproductive health strategies. Thus, this study's primary goal is to delve into the factors which impact miscarriages that take place prior to and following the first 12 weeks of gestation.

METHODS

The bivariate analysis was employed to determine the frequency of miscarriages. The factors associated with miscarriages in the first (≤12 weeks) and second & above (> 12 weeks) trimesters of pregnancy were then examined using a generalised linear regression model, with 95% confidence intervals. Finally, we use ArcGIS to illustrate the prevalence of miscarriage in the districts of India.

RESULTS

Our result shows that miscarriages occur often in India (4.9%), with 23% of cases occurring in the first trimester (≤12 weeks). In our bivariate analysis, we identified several factors associated with a higher prevalence of miscarriages in India. It was found that mothers aged thirty years or older, residing in urban areas, with less than ten years of education, belonging to the richest wealth quantile, expressing a desire for more children, having no demand for contraception, and possessing no parity experienced a higher prevalence of miscarriage in total pregnancies in India. On the other hand, the generalised linear model's findings show that mothers who are thirty years of age or older, practise other religions, live in urban areas, are members of other castes, want more children, marry before the age of eighteen, and meet their contraceptive needs are more likely to have miscarriages in total pregnancy. However, there is a larger likelihood of miscarriage in the first trimester (≤12 weeks) for mothers who follow other religions, live in urban areas, are from Other Backward Class (OBC), get married before the age of eighteen, and fall into the middle and upper wealth quantiles. A mother is more likely to miscarriage in the second & above (> 12 weeks) trimesters if she is older than thirty, from other castes, wants more children, has moderate media exposure, marries before turning eighteen, meets her contraceptive needs, and does not feel the need for contraception. After accounting for socioeconomic characteristics, all results were statistically significant.

CONCLUSIONS

Given the substantial number of miscarriages in India, police need to improve planning and guidance in order to lower pregnancy loss due to miscarriage. Miscarriage rates may be significantly decreased by enhancing the availability and quality of reproductive health care infrastructure, particularly in rural areas.

Risk factors and glycaemic control in small-for-gestational-age infants born to mothers with gestational diabetes mellitus: a case-control study using propensity score matching based on a large population

BACKGROUND

Small for gestational age (SGA) poses a significant concern for newborns, being linked to neonatal complications and potential metabolic disorders in adulthood, especially when born to mothers with gestational diabetes mellitus (GDM), elevating their risk of complications and mortality. However, the pregnancy risk factors and glycaemic control associated with SGA infants born to mothers with GDM remain unclear.

AIM

To identify the pregnancy risk factors and glycaemic control associated with SGA infants born to mothers with GDM.

METHOD

This case-control study was conducted among 1910 women with GDM in China. Data were collected by the integrated electronic medical record system. Using 1:4 propensity score matching analysis, we adjusted for gestational age as confounder. Univariate and multivariate analyses were performed to identify risk factors.

RESULTS

Risk factors for SGA born to mothers with GDM included a history of low birth weight, gestational hypertension, oligohydramnios, short maternal height, underweight pre-pregnancy body mass index and inadequate weight growth. While SGA was protected by weakly positive ketonuria levels in the first trimester, multiparous, anaemia and previous uterine scar were protective factors for SGA. Moreover, 2-hour postprandial glucose and haemoglobin A1c in the second trimester, as well as the 0-hour and 2-hour 75 g oral glucose tolerance test (OGTT) were linked to risk of SGA.

CONCLUSIONS

SGA infants are the result of multifactorial interactions among GDM pregnant women. Notably, glycaemic control levels were associated with SGA. There is a need for enhanced perinatal monitoring and antenatal care to reduce SGA.

Birthweight of the subsequent singleton pregnancy following a first twin or singleton pregnancy

INTRODUCTION

Birthweight is an important pregnancy indicator strongly associated with infant, child, and later adult life health. Previous studies have found that second-born babies are, on average, heavier than first-born babies, indicating an independent effect of parity on birthweight. Existing data are mostly based on singleton pregnancies and do not consider higher order pregnancies. We aimed to compare birthweight in singleton pregnancies following a first twin pregnancy relative to a first singleton pregnancy.

MATERIAL AND METHODS

This was a prospective registry-based cohort study using maternally linked offspring with first and subsequent pregnancies registered in the Medical Birth Registry of Norway between 1967 and 2020. We studied offspring birthweights of 778 975 women, of which 4849 had twins and 774 126 had singletons in their first pregnancy. Associations between twin or singleton status of the first pregnancy and birthweight (grams) in subsequent singleton pregnancies were evaluated by linear regression adjusted for maternal age at first delivery, year of first pregnancy, maternal education, and country of birth. We used plots to visualize the distribution of birthweight in the first and subsequent pregnancies.

RESULTS

Mean combined birthweight of first-born twins was more than 1000 g larger than mean birthweight of first-born singletons. When comparing mean birthweight of a subsequent singleton baby following first-born twins with those following first-born singletons, the adjusted difference was just 21 g (95% confidence interval 5-37 g).

CONCLUSIONS

Birthweights of the subsequent singleton baby were similar for women with a first twin or a first singleton pregnancy. Although first twin pregnancies contribute a greater combined total offspring birthweight including more extensive uterine expansion, this does not explain the general parity effect seen in birthweight. The physiological reasons for increased birthweight with parity remain to be established.

The smaller firstborn: exploring the association of parity and fetal growth

PURPOSE

To investigate the association of parity with a range of neonatal anthropometric measurements in a cohort of uncomplicated term singleton pregnancies.

METHODS

Retrospective cohort study of patients with a singleton term birth at a single tertiary center (2014-2020) was carried out. The primary exposure was parity. The following neonatal anthropometric measures were considered: birthweight, head circumference, length, ponderal index, and neonatal body mass index (BMI).

RESULTS

A total of 8134 patients met the study criteria, 1949 (24.0%) of whom were nulliparous. Compared with multiparous patients, infants of nulliparous patients had a lower mean percentile for birthweight (43.1 ± 26.4 vs. 48.3 ± 26.8 percentile, p < 0.001), head circumference (44.3 ± 26.4 vs. 48.1 ± 25.5 percentile, p < 0.001), length (52.6 ± 25.1 vs. 55.5 ± 24.6 percentile, p < 0.001), ponderal index (34.4 ± 24.0 vs. 37.6 ± 24.2 percentile, p < 0.001), and BMI (39.1 ± 27.1 vs. 43.9 ± 27.3 percentile, p < 0.001). In addition, infants of nulliparous patients had higher odds of having a small (< 10th percentile for gestational age) birthweight (aOR 1.32 [95% CI 1.12-1.56]), head circumference (aOR 1.54 [95% CI 1.29-1.84]), length (aOR 1.50 [95% CI 1.16-1.94]), ponderal index (aOR 1.30 [95% CI 1.12-1.51]), and body mass index (aOR 1.42 [95% CI 1.22-1.65]). Most neonatal anthropometric measures increased with parity until a parity of 2, where it seemed to reach a plateau.

CONCLUSION

Parity has an independent impact on a wide range of neonatal anthropometric measures, suggesting that parity is associated with both fetal skeletal growth and body composition. In addition, the association of parity with fetal growth does not follow a continuous relationship but instead reaches a plateau after the second pregnancy.

Secular trends of low birth weight, preterm birth, and small for gestational age in Shanghai from 2004 to 2020: an age-period-cohort analysis

BACKGROUND

Although highly heterogeneous among countries, the incidence rates of low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA) have been increasing globally over the past two decades. To better understand the cause of these secular trends, this study aimed to investigate the effects of age, period, and birth cohort on LBW, PTB, and SGA rates in Shanghai.

METHODS

Data from 2,958,695 singleton live births at 24-41 gestational weeks between 2004 and 2020 were obtained for this study. Age-period-cohort models based on Poisson regression were used to evaluate the independent effects of maternal age, delivery period, and maternal birth cohort on the trends in LBW, PTB, and SGA.

RESULTS

The overall prevalence rates of LBW, PTB, and SGA were 2.9%, 4.7%, and 9.3%, respectively, and significant changes were observed (average annual change: + 10.7‰, + 9.1‰, -11.9‰) from 2004 to 2020. Cohort effect increased steadily, from 1960 (risk ratio [RR] = 0.71, 95% confidence interval [CI]: 0.65-0.78) to 1993 (RR = 0.97, 95% CI: 0.94-1.01) for LBW and from 1960 (RR = 0.69, 95% CI: 0.64-0.75) to 2004 (RR = 1.02, 95% CI: 0.94-1.12) for PTB. A strong cohort effect was found with the highest risk of SGA (RR = 1.82, 95% CI: 1.72-1.93) in 1960 and the lowest risk (RR = 0.57, 95% CI: 0.54-0.61) in 2004, compared with the reference cohort of 1985. There was a "U-shaped" maternal age effect on LBW and PTB and a weak period effect on the three birth outcomes.

CONCLUSIONS

Our findings suggested a significant independent effect of age, period, and birth cohort on the three birth outcomes. The increasing rates of LBW and PTB motivated us to focus on young and advanced pregnant women. Meanwhile, the prevalence of SGA decreased steadily, illustrating the need for further research on the mechanisms underlying these trends.

Effect of Parity on Placental Histopathology Features in Singleton Live Births Following IVF

The aim of this study was to evaluate the effect of parity (primipara vs multipara) on the histopathology of the placenta in singleton live births following in vitro fertilization. We conducted a retrospective cohort study evaluating data of all IVF resulted live births from one university affiliated hospital during 2009-2017. All patients had the placenta sent for pathological evaluation. Exclusion criteria were history of miscarriage or elective termination of pregnancy, abnormal uterine cavity findings, previous uterine surgery, in vitro maturation cycles, gestational carrier cycles, oocyte recipient cycles, preimplantation genetic diagnosis cycles, and multiple pregnancies. The outcomes measured included anatomical, inflammation, vascular malperfusion, and villous maturation placental features. A multivariate analysis was conducted to adjust the results for factors potentially associated with placental pathology features. A total of 395 live births were included in the final analysis and were allocated to the study groups according to parity: primipara (n = 273) and multipara (n = 122). After adjustment for potential confounding factors, multiparity was found to be significantly associated with delayed villous maturation (OR 4.9; 95% CI 1.2-19.8) and primiparity was significantly associated with maternal vascular malperfusion (OR 0.6; 95% CI 0.3-0.8). We showed that parity has an impact on placental histopathological changes which in turn may affect perinatal outcome.

A Retrospective Cohort Study to Determine Whether the Previous Route of Delivery Affects the Uterine Artery Blood Flow

INTRODUCTION

 In our study, we aimed to investigate the effect of the previous delivery route on uterine artery pulsatility index (PI) and obstetric outcome. We aim to assess the effects of previous cesarean delivery (CD) and placental location on first- and second-trimester uterine artery Doppler indices as well as first-trimester pregnancy-associated plasma protein-A (PAPP-A) multiples of the median (MoM) levels in the subsequent pregnancy.

MATERIALS AND METHODS

 We designed a retrospective cohort study to collect the participants' clinical and uterine artery Doppler. Data regarding pregnant women's first- and second-trimester exams, who were referred to our maternal-fetal medicine unit, were collected from hospital records between June 2015 and December 2019.

RESULTS

 Uterine artery PI MoM values were not different between the cases with the anterior and non-anterior placental locations. No significant difference was found in the first- and second-trimester uterine artery PI MoM values by delivery route (p = 0.57). However, the intrauterine growth restriction rate was higher in the CD group (p < 0.001).

CONCLUSION

 In this study, we compared the uterine blood flow indices between the previous cesarean and vaginal delivery groups. We observed no significant difference between the patients with different delivery routes.

Development and Validation of a Small for Gestational Age Screening Model at 21-24 Weeks Based on the Real-World Clinical Data

BACKGROUND

Small for gestational age (SGA) is a condition in which fetal birthweight is below the 10th percentile for the gestational age, which increases the risk of perinatal morbidity and mortality. Therefore, early screening for each pregnant woman is of great interest. We aimed to develop an accurate and widely applicable screening model for SGA at 21-24 gestational weeks of singleton pregnancies.

METHODS

This retrospective observational study included medical records of 23,783 pregnant women who gave birth to singleton infants at a tertiary hospital in Shanghai between 1 January 2018 and 31 December 2019. The obtained data were nonrandomly classified into training (1 January 2018 to 31 December 2018) and validation (1 January 2019 to 31 December 2019) datasets based on the year of data collection. The study variables, including maternal characteristics, laboratory test results, and sonographic parameters at 21-24 weeks of gestation were compared between the two groups. Further, univariate and multivariate logistic regression analyses were performed to identify independent risk factors for SGA. The reduced model was presented as a nomogram. The performance of the nomogram was assessed in terms of its discrimination, calibration, and clinical usefulness. Moreover, its performance was assessed in the preterm subgroup of SGA.

RESULTS

Overall, 11,746 and 12,037 cases were included in the training and validation datasets, respectively. The developed SGA nomogram, comprising 12 selected variables, including age, gravidity, parity, body mass index, gestational age, single umbilical artery, abdominal circumference, humerus length, abdominal anteroposterior trunk diameter, umbilical artery systolic/diastolic ratio, transverse trunk diameter, and fasting plasma glucose, was significantly associated with SGA. The area under the curve value of our SGA nomogram model was 0.7, indicating a good identification ability and favorable calibration. Regarding preterm SGA fetuses, the nomogram achieved a satisfactory performance, with an average prediction rate of 86.3%.

CONCLUSIONS

Our model is a reliable screening tool for SGA at 21-24 gestational weeks, especially for high-risk preterm fetuses. We believe that it will help clinical healthcare staff to arrange more comprehensive prenatal care examinations and, consequently, provide a timely diagnosis, intervention, and delivery.

Exposure of ambient PM2.5 during gametogenesis period affects the birth outcome: Results from the project ELEFANT

Various environmental and behavioural factors influence neonatal health. Gamete formation (gametogenesis) is a crucial period which affects embryo development and neonatal health and ambient air pollution exposure at this stage may lead to an adverse birth outcome. Previous epidemiological and toxicological research demonstrated a strong association between maternal ambient air pollution exposure and adverse birth outcomes. However, the joint exposure-outcome of paternal exposure (76 days before the last menstruation and 14 days after the last menstruation) and maternal exposure (14 days after the last menstruation) when exploring the mechanism of the influence of air pollutants on pregnancy outcome and neonatal health remains unexplored. Here, in the Project Environmental and LifEstyle FActors iN metabolic health throughout life-course Trajectories (ELEFANT), we collected the data of 10,960 singleton pregnant women with 24-42 completed gestational weeks and included them in this study. A multinominal logistic regression model was applied to investigate the association between adverse birth outcomes and ambient PM_2.5 exposure levels during spermatogenesis and oogenesis. Results from the binary classification of ambient PM_2.5 exposure showed that the risk of abnormal birthweight was significantly greater when ambient PM_2.5 exposure was both higher during spermatogenesis and oogenesis, with RRs of 1.86 (95% CI: 1.02, 3.39). The risk of macrosomia (RR: 1.88 (95% CI: 1.13, 3.12)) increased significantly when ambient PM_2.5 levels were higher during spermatogenesis. Primiparity and primigravity are more likely to be influenced by higher ambient PM_2.5 levels during spermatogenesis. In conclusion, more attention should be paid to higher exposure level of ambient PM_2.5 during spermatogenesis.

Joint Exposure to Ambient Air Pollutants Might Elevate the Risk of Small for Gestational Age (SGA) Infants in Wuhan: Evidence From a Cross-Sectional Study

Objective: To investigate the effect of exposure to multiple ambient air pollutants during pregnancy on the risk of children being born small for gestational age (SGA). Methods: An Air Pollution Score (APS) was constructed to assess the effects of being exposed to six air pollutants simultaneously, PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ (referred to as joint exposure). A logistic regression model was applied to estimate the associations of APS and SGA. Results: The adjusted odds ratios (ORs) of SGA per 10 ug/m³ increased in APS during the first and second trimesters and the entire pregnancy were 1.003 [95% confidence intervals (CIs): 1.000, 1.007], 1.018 (1.012, 1.025), and 1.020 (1.009, 1.031), respectively. The ORs of SGA for each 10 μg/m³ elevated in APS during the whole pregnancy were 1.025 (1.005, 1.046) for mothers aged over 35 years old vs. 1.018 (1.005, 1.031) for mothers aged under 35 years old. Women who were pregnant for the first time were more vulnerable to joint ambient air pollution. Conclusion: In summary, the results of the present study suggested that joint exposure to ambient air pollutants was associated with the increment in the risks of SGA.

Uterine artery Doppler indices throughout gestation in women with and without previous Cesarean deliveries: a prospective longitudinal case-control study

To determine whether a history of previous Cesarean delivery (CD) impacts uterine artery (UtA) Doppler indices throughout pregnancy. Women with and without CD (NCD) were prospectively enrolled for sequential assessments of the UtA mean/median pulsatility index (UtA-PI), resistance index (UtA-RI), and systolic/diastolic ratio (UtA-S/D) at 11-13 + 6, 14-19 + 6, 30-34 + 6, and 35-37 + 6 weeks' gestation. Data from 269/269, 246/257, 237/254, and 219/242 CD/NCD participants from each gestational period were available for analysis. Multiples of the median (MoMs) of UtA Doppler indices showed biphasic temporal (Δ) pattern; with an initial dropping until the second trimester, then a subsequent elevation until late in pregnancy (p < 0.05). The measurements and Δs of the UtA indices between CD and NCD were not different (p > 0.05). Mixed-effects modelling ruled out effects from nulliparity (n = 0 and 167 for CD and NCD, respectively) (p > 0.05). History of CD neither influenced the measurements nor the temporal changes of the UtA Doppler indices throughout pregnancy. The biphasic Δs of UtA Doppler indices added to the longitudinal data pool, and may aid in future development of a more personalized prediction using sequential/contingent methodologies, which may reduce the false results from the current cross-sectional screening.

Low birth weight and its associated risk factors in a rural health district of Burkina Faso: a cross sectional study

Background

Low birth weight (LBW) is a major factor of neonate mortality that particularly affects developing countries. However, the scarcity of data to support decision making to reduce LBW occurrence is a major obstacle in sub-Saharan Africa. The aim of this research was to determine the prevalence and associated factors of LBW at the Yako health district in a rural area of Burkina Faso.

Methods

A cross sectional survey was conducted at four peripheral health centers among mothers and their newly delivered babies. The mothers’ socio-demographic and obstetrical characteristics were collected by face-to-face interview or by review of antenatal care books. Maternal malaria was tested by standard microscopy and neonates’ birth weights were documented. Multivariate logistic regression was used to determine factors associated with LBW. A p-value < 0.05 was considered statistically significant.

Results

Of 600 neonates examined, the prevalence of low birth weight was 11.0%. Adjustment for socio-demographic characteristic, medical conditions, obstetrical history, malaria prevention measures by multivariate logistic regression found that being a primigravid mother (aOR = 1.8, [95% CI: 1.1–3.0]), the presence of malaria infection (aOR = 1.9, [95% CI: 1.1–3.5]), the uptake of less than three doses of sulfadoxine-pyrimethamine for the intermittent preventive treatment of malaria in pregnancy (IPTp-SP) (aOR = 2.2, [95% CI: 1.3–3.9]), the presence of maternal fever at the time of delivery (aOR = 2.8, [95% CI: 1.5–5.3]) and being a female neonate (aOR = 1.9, [95% CI: 1.1–3.3]) were independently associated with an increased risk of LBW occurrence. The number of antenatal visits performed by the mother during her pregnancy did not provide any direct protection for low birth weight.

Conclusion

The prevalence of LBW remained high in the study area. Maternal malaria, fever and low uptake of sulfadoxine-pyrimethamine doses were significantly associated with LBW and should be adequately addressed by public health interventions.

Magnitude of low birthweight in malaria endemic settings of Nanoro, rural Burkina Faso: a secondary data analysis

Low birthweight (LBW) is a worldwide problem that particularly affects developing countries. However, limited information is available on its magnitude in rural area of Burkina Faso. This study aimed to estimate the prevalence of low birthweight and to identify its associated factors in Nanoro health district. A secondary analysis of data collected during a cross-sectional survey was conducted to assess the prevalence of low birthweight in Nanoro health and demographic surveillance system area (HDSS). Maternal characteristics extracted from antenatal care books or by interview, completed by malaria diagnosis were examined through a multi-level logistic regression to estimate odd-ratios of association with low birthweight. Significance level was set at 5%. Of the 291 neonates examined, the prevalence of low birthweight was 12%. After adjustment for socio-demographic, obstetric and malaria prevention variables, being primigravid (OR = 8.84, [95% CI: 3.72-21.01]), or multigravid with history of stillbirth (OR = 5.03, [95% CI: 1.54-16.40]), as well as the lack of long-lasting insecticide treated bed net use by the mother the night preceding the admission for delivery (OR = 2.5, [95% CI: 1.1-5.9]) were significantly associated with neonate low birthweight. The number of antenatal visits however did not confer any direct benefit on birthweight status within this study area. The prevalence of low birthweight was high in the study area and represents an important public health problem in Burkina Faso. In light of these results, a redefinition of the content of the antenatal care package is needed.

Parity and the risks of adverse birth outcomes: a retrospective study among Chinese

Background

Nulliparity is considered to be a risk factor of preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA). With the new two-child policy launched in 2016, more Chinese women have delivered their 2nd baby. Yet few studies have assessed the impact of parity on adverse birth outcomes in China. This study aimed to examine the association between parity and risks of PTB, LBW and SGA in a Chinese population. The combined effects of maternal age and parity on adverse birth outcomes were also assessed.

Methods

This retrospective study included all non-malformed live births born during January 1, 2014 and December 31, 2018 in Chengdu, China. A total of 746,410 eligible live singletons with complete information were included in the analysis. Parity was classified into nulliparity (i.e. has never delivered a newborn before) and multiparity (i.e. has delivered at least one newborn before). Log-binomial regression analyses were applied to evaluate the association between parity and PTB, LBW and SGA. We further divided maternal age into different groups (< 25 years, 25–29 years, 30–34 years and ≥ 35 years) to assess the combined effects of maternal age and parity on adverse birth outcomes.

Results

Multiparity was associated with reduced risks of PTB (aRR = 0.91, 95% CI: 0.89–0.93), LBW (aRR = 0.74, 95% CI: 0.72–0.77) and SGA (aRR = 0.67, 95% CI: 0.66–0.69) compared with nulliparity. In each age group, we observed that multiparity was associated with lower risks of adverse birth outcomes. Compared to nulliparous women aged between 25 and 29 years, women aged ≥35 years had greater risks of PTB and LBW, regardless of their parity status. In contrast, multiparous women aged ≥35 years (aRR = 0.73, 95% CI: 0.70–0.77) and those aged < 25 years (aRR = 0.88, 95% CI: 0.84–0.93) were at lower risk of SGA compared with nulliparous women aged between 25 and 29 years.

Conclusion

Multiparity was associated with lower risks of all adverse birth outcomes. Special attention should be paid to nulliparous mothers and those with advanced age during antenatal care, in order to reduce the risks of adverse birth outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03718-4.

Geographical Distribution and Risk Factors of Low Birth Weight in Nigeria

BACKGROUND

Low birth weight (LBW) directly or indirectly accounts for 60% to 80% of all neonatal deaths globally, and it has become an issue of serious health concern with Nigeria with one of the highest infant mortality rates (74/1,000) in the world. Despite the severe health impact, little is understood on the geographical differences in maternal socioeconomic and environmental factors that affect LBW across the states in Nigeria.

METHOD

Using the spatial epidemiological approach, this study examined the geographical variations in LBW and associated risk factors in Nigeria with the aid of spatial statistics.

RESULTS

There was a regional LBW corridor in the extreme north with Yobe state with the highest prevalence rate. Maternal educational attainment and acute maternal malnutrition explained 65.4% (ordinary least squares model) and 70.5% (spatial error model, SEM) of the variation in the geographical pattern of LBW.

CONCLUSION

LBW remains an issue of serious health concern in Nigeria. The finding of this study would shed more light on the spatial epidemiology of LBW in Nigeria and also guide public health programs in curtailing the high prevalence rate of LBW.

RECOMMENDATIONS

The study recommends health education on nutrition in pregnancy and the need to improve health literacy among women so as to check the high LBW prevalence.

Risk factors and fetal outcomes for preeclampsia in a Colombian cohort

In Latin America and the Caribbean, hypertensive pregnancy disorders are responsible for almost 26% of all maternal deaths [1] and, in Colombia, they account for 59% of all severe maternal morbidity (SMM) cases, and 59.7% of all SMM cases in adolescents [2]. One of the most important hypertensive pregnancy disorders is preeclampsia (PE). Lives can be saved, if PE is prevented, or detected early and properly managed. Prevention and detection depend on identifying the risk factors associated with PE, and, as these have been shown vary by population, they should be determined on a population-by-population basis. The following study utilized the nested case-control model to evaluate 45 potential PE risk factors of a cohort in Bogotá, Colombia, making it perhaps the most comprehensive study of its kind in Colombia. It found PE to have a statistically significant association with 7 of the 45 factors evaluated: 1) pre-gestational BMI >30 kg/m², 2) pregnancy weight gain >12 kg, 3) previous history preeclampsia/eclampsia, 4) previous history of IUGR-SGA (Intrauterine Growth Restriction-Small for Gestational Age), 5) maternal age <20 or ≥35 years (20–34 was not associated), and 6) family history of diabetes. Finally, prenatal consumption of folic acid was found to lower the risk of PE. We recommend that, in Colombia, factors 1–6 be used to identify at risk mothers during pregnancy check-ups; that mothers be encouraged to take folic acid during pregnancy; and, that Colombia's health system and public policy address the problem of pregestational obesity.

Risk factors for low birth weight among rural and urban Malaysian women

BACKGROUND

Low birth weight prevalence in Malaysia remains high. Socioeconomic background may lead to differences in physical activity and maternal nutritional status, which may play an important role in birth outcomes.

METHODS

This prospective cross-sectional study aimed to identify rural-urban differences in risk factors for low birth weight among women in Malaysia. Pregnant women at ≥20 weeks of gestation in urban and rural Malaysia (n = 437) completed questionnaires on sociodemographic characteristics and physical activity. Weight and middle-upper arm circumference were measured. Infant birth outcomes were extracted from medical records.

RESULTS

The overall prevalence of low birth weight infants was 6.38%. Rural women had more low birth weight infants than urban women (9.8% vs 2.0%, p = 0.03). Findings showed rural women were less sedentary (p = 0.003) and participated in more household/caregiving activities (p = 0.036), sports activities (p = 0.01) and less occupational activity (p < 0.001) than urban women. Logistic regression revealed that older age (OR = 1.395, 95% Cl = 1.053 to 1.846), low parity (OR = 0.256, 95% Cl = 0.088-0.747) and low middle-upper arm circumference (OR = 0.738, 95% Cl = 0.552 to 0.987) increased the risk of low birth weight infants in rural, but not in urban women.

CONCLUSIONS

We observed differences in risk factors for low birth weight between urban and rural pregnant women. Age, malnutrition and low parity were risk factors for low birth weight among rural pregnant women. Our findings suggest that rural pregnant women with low nutritional status should be encouraged to monitor their middle-upper arm circumference consistently throughout pregnancy. Improving nutritional status in rural pregnant women may reduce the risk of low birth weight infants in this population.

How much does the uterus matter? Perinatal outcomes are improved when donor oocyte embryos are transferred to gestational carriers compared to intended parent recipients

OBJECTIVE

To assess the reproductive and neonatal outcomes of cycles in which donor oocyte embryos were transferred to gestational carriers compared to intended parent recipients.

DESIGN

Retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Intended parent recipients and gestational carriers receiving donor oocyte embryos in 2014 in the United States.

INTERVENTIONS(S)

None.

MAIN OUTCOMES MEASURE(S)

Clinical pregnancy, live birth, miscarriage, plurality, prematurity, and birth weight from pregnancies conceived with donor oocyte embryos transferred to either a gestational carrier or an intended parent recipient.

RESULT(S)

The mean ages of intended parent recipients (N=18,317) and gestational carriers (N=1,927) were 41.6 and 31.6 years, respectively. Compared to an intended parent recipient, patients using a gestational carrier had significantly higher odds of a clinical pregnancy (65.2% vs. 56.3%, adjusted odds ratio (aOR) 1.33, 95% confidence interval (CI) 1.17-1.51) and live birth (57.1% vs. 46.4%, aOR 1.37, 95% CI 1.21-1.55) using fresh or frozen donor-oocyte embryos. Of the singletons born (n=716 using a gestational carrier and n=5,632 in intended parent recipients), the incidence of prematurity was significantly lower in gestational carriers compared to intended parent recipients (17.5% vs. 25.4%, aOR 0.78, 95% CI 0.61-0.99). The incidence of low birthweight among singletons was significantly reduced in gestational carrier cycles (6.4% vs. 12.1%, aOR 0.62, 95% CI 0.44-0.89).

CONCLUSION

Intended parent recipients had decreased pregnancy rates and poorer neonatal outcomes compared to a gestational carrier. This suggests that a history of infertility adversely affects the uterine microenvironment, independent of the oocyte.

Pregnancy Outcomes in Women of Advanced Maternal Age: a Retrospective Cohort Study from China

This retrospective cohort study attempts to investigate pregnancy complications and adverse pregnancy outcomes in women of advanced maternal age (AMA). Data were extracted from electronic medical records system at West China Second University Hospital of Sichuan University from January 2013 to July 2016. The study cohort consisted 8 subgroups of women on 4 different age levels (20-29 years, 30-34 years, 35-39 years and ≥40 years) and 2 different parities (primiparity and multiparity). In the study period, 38811 women gave birth at our hospital, a randomized block was used to include 2800 women of singleton pregnancy >28 gestational weeks, with 350 patients in each subgroup. Maternal complications and fetal outcomes were collected and defined according to relevant guidelines. Confounding factors representing maternal demographic characteristics were identified from previous studies and analysed in multivariate analysis. There was an increasing trend for the risks of adverse pregnancy outcomes with increasing age, especially in AMA groups. Our study showed that AMA, primiparity, maternal overweight or obesity, lower educational level and residence in rural area increased pregnancy complications and adverse fetal outcomes. Increased professional care as well as public concern is warranted.

Prenatal air pollution exposure, smoking, and uterine vascular resistance

Supplemental Digital Content is available in the text.

Background:

Prenatal exposure to air pollution and smoking increases the risk of pregnancy complications and adverse birth outcomes, but pathophysiologic mechanisms are still debated. Few studies to date have examined the influence of air pollution on uterine vascular resistance, and no studies have examined the independent impact of these exposures. We aimed to assess the impact of prenatal exposure to traffic-related air pollution and smoking on uterine vascular resistance.

Methods:

Our study included 566 pregnant women recruited between 1993 and 1996 in Los Angeles who completed visits at three gestational ages. Information on smoking was collected, and uterine vascular resistance was measured at each visit by Doppler ultrasound. We calculated three resistance indices: the resistance index, the pulsatility index, and the systolic/diastolic ratio. We estimated exposure to NO₂ at the home address of the mother using a land use regression model and to nitrogen oxides using CALINE4 air dispersion modeling. We used generalized linear mixed models to estimate the effects of air pollution and smoking on uterine vascular resistance indices.

Results:

Land use regression–derived NO₂ and CALINE4-derived nitrogen oxides exposure increased the risk of high uterine artery resistance in late pregnancy. Smoking during pregnancy also increased the risk of higher uterine resistance and contributed to bilateral notching in mid-pregnancy.

Conclusion:

Our results suggest that uterine vascular resistance is a mechanism underlying the association between smoking and air pollution and adverse birth outcomes.

Nulliparity is associated with subtle adverse metabolic outcomes in overweight/obese mothers and their offspring

BACKGROUND

We aimed to evaluate metabolic outcomes in overweight/obese nulliparous and multiparous women and their offspring.

STUDY DESIGN

Seventy-two overweight and obese women who participated in a randomized controlled trial of exercise in pregnancy were included in the study, comparing 18 nulliparous and 54 multiparous women and their singleton offspring. Women were assessed at 19 and 36 weeks of gestation. Fetal growth was measured using standard obstetric ultrasound techniques. Cord blood was collected at birth. Maternal and offspring body composition was assessed using DXA ~2 weeks after delivery.

RESULTS

Nulliparous women had higher HbA1c in the third trimester of pregnancy than multiparous women (5.48% vs 5.29%; P=.002) and were more insulin-resistant based on the surrogate marker sex hormone-binding globulin (354 vs 408 nmol/L; P=.047). Nulliparous women also had higher levels of the inflammatory marker tumour necrosis factor-alpha (4.74 vs 3.62 pg/mL; P=.025). At birth, the offspring of nulliparous women were on average 340 g (P=.013) and 0.69 standard deviation scores (P=.026) lighter than those born of multiparous women. Cord blood data showed lower insulin-like growth factor-II (P=.026) and higher IGF binding protein-1 (P=.002) levels in the offspring of nulliparous women. In addition, a less favourable metabolic profile was observed in the offspring of nulliparous women, as indicated by higher triglyceride (P<.001) and interleukin-6 (P=.039) concentrations.

CONCLUSIONS

Infants born of nulliparous overweight and obese women appear to be exposed to a less favourable metabolic environment in utero, with evidence of subtle adverse metabolic outcomes at birth compared to infants of overweight/obese multiparous women.

The impact of delayed maternity on foetal growth in Spain: An assessment by population attributable fraction

BACKGROUND

Delayed childbearing is considered a risk factor for maternal-foetal health. As in other higher-income countries, in Spain age at maternity has steadily increased during the last two decades.

AIM

To quantify the impact of the delay in the age at maternity on small for gestational age (SGA) categories of <3rd, 3rd-5th and 5th-10th percentiles.

METHODS

2,672,350 singleton live births born to Spanish mothers in 2007-2015 were analysed. Adjusted relative risk was calculated to estimate the adjusted partial population attributable fractions (PAF_p) for mothers aged 35-39 and ≥40 years for each category of SGA considering the interaction between age at maternity and parity.

FINDINGS

Primipara 35-39 years old mothers have the highest PAF_p in the three categories of SGA, with the maximum value for SGA <3rd percentile (2.57%, 95% CI 2.25, 2.88). PAF_p for both primipara and multipara ≥40 years old mothers were less than 1%. PAF_p for primipara older mothers increased significantly in 2007-2015 for the three categories of SGA, more clearly among those aged 35-39 years. The contribution of multipara mothers of both age groups did not increase significantly during the period.

CONCLUSION

Delayed maternity is a significant adjusted risk factor for SGA, contributing to the increase of its prevalence. However, results also suggest a limited clinical impact of delayed maternity on foetal growth. Positive changes in maternal profile associated with the shift in maternal age might contribute to explain the limited impact of mothers aged 35 years and older on negative birth outcome in Spain.

New birthweight charts according to parity and type of delivery for the Spanish population

OBJECTIVE

Birthweight by gestational age charts enable fetal growth to be evaluated in a specific population. Given that maternal profile and obstetric practice have undergone a remarkable change over the past few decades in Spain, this paper presents new Spanish reference percentile charts stratified by gender, parity and type of delivery. They have been prepared with data from the 2010-2014 period of the Spanish Birth Statistics Bulletin.

METHODS

Reference charts have been prepared using the LMS method, corresponding to 1,428,769 single, live births born to Spanish mothers. Percentile values and mean birth weight are compared among newborns according to gender, parity and type of delivery.

RESULTS

Newborns to primiparous mothers show significantly lower birthweight than those born to multiparous mothers (p<0.036). Caesarean section was associated with a substantially lower birthweight in preterm births (p<0.048), and with a substantially higher birthweight for full-term deliveries (p<0.030). Prevalence of small for gestational age is significantly higher in newborns born by Caesarean section, both in primiparous (p<0.08) and multiparous mothers (p<0.027) and, conversely, the prevalence of large for gestational age among full-term births is again greater both in primiparous (p<0.035) and in multiparous mothers (p<0.007).

CONCLUSIONS

Results support the consideration of establishing parity and type of delivery-specific birthweight references. These new charts enable a better evaluation of the impact of the demographic, reproductive and obstetric trends currently in Spain on fetal growth.

Postponing parenthood to advanced age

The aim of the Postponing Parenthood project was to investigate several aspects of the delaying of childbearing phenomenon in Sweden and Norway, such as medical risks and parental experiences. Data were retrieved from the Swedish and Norwegian Medical Birth Registers and three different cohorts: the Swedish Young Adult Panel Study, the Norwegian Mother and Child Cohort, and the Swedish Women's Experiences of Childbirth cohort. Postponing childbirth to age 35 years and later increased the risk of rare but serious pregnancy outcomes, such as stillbirth and very preterm birth. Older first-time parents were slightly more anxious during pregnancy, and childbirth overall was experienced as more difficult, compared with younger age groups. First-time mothers' satisfaction with life decreased from about age 28 years, both when measured during pregnancy and early parenthood. Delaying parenthood to mid-30 or later was more related to lifestyle than socioeconomic factors, suggesting that much could be done in terms of informing young persons about the limitations of fertility and assisted reproductive techniques, and the risks associated with advanced parental age.

Advanced maternal age increases the risk of very preterm birth, irrespective of parity: a population-based register study

OBJECTIVE

To investigate whether advanced maternal age is associated with preterm birth, irrespective of parity.

DESIGN

Population-based registry study.

SETTING

Swedish Medical Birth Register.

POPULATION

First, second, and third live singleton births to women aged 20 years or older in Sweden, from 1990 to 2011 (n = 2 009 068).

METHODS

Logistic regression analysis was used in each parity group to estimate risks of very and moderately preterm births to women at 20-24, 25-29, 30-34, 35-39, and 40 years or older, using 25-29 years as the reference group. Odds ratios (ORs) were adjusted for year of birth, education, country of birth, smoking, body mass index, and history of preterm birth. Age-related risks of spontaneous and medically indicated preterm births were also investigated.

MAIN OUTCOME MEASURES

Very preterm (22-31 weeks of gestation) and moderately preterm (32-36 weeks) births.

RESULTS

Risks of very preterm birth increased with maternal age, irrespective of parity: adjusted ORs in first, second, and third births ranged from 1.18 to 1.28 at 30-34 years, from 1.59 to 1.70 at 35-39 years, and from 1.97 to 2.40 at ≥40 years. In moderately preterm births, age-related associations were weaker, but were statistically significant from 35-39 years in all parity groups. Advanced maternal age increased the risks of both spontaneous and medically indicated preterm births.

CONCLUSIONS

Advanced maternal age is associated with an increased risk of preterm birth, irrespective of parity, especially very preterm birth. Women aged 35 years and older, expecting their first, second, or third births, should be regarded as a risk group for very preterm birth.

TWEETABLE ABSTRACT

Women aged 35 years and older should be regarded as a risk group for very preterm birth, irrespective of parity.

Reference ranges for uterine artery pulsatility index during the menstrual cycle: a cross-sectional study

BACKGROUND

Cyclic endometrial neoangiogenesis contributes to changes in local vascular patterns and is amenable to non-invasive assessment with Doppler sonography. We hypothesize that the uterine artery (UtA) impedance, measured by its pulsatility index (PI), exhibits a regular pattern during the normal menstrual cycle. Therefore, the main study objective was to derive normative new day-cycle-based reference ranges for the UtA-PI during the entire cycle from days 1 to 34 according to the isolated time effect and potential confounders such as age and parity.

METHODS

From January 2009 to December 2012, a cross-sectional study of 1,821 healthy women undergoing routine gynaecological ultrasound was performed. The Doppler flow of the right and left UtA-PI was studied transvaginally by colour and pulsed Doppler imaging. The mean right and left values and the presence or absence of a bilateral protodiastolic notch were recorded. Reference intervals for the PI according to the cycle day were generated by classical linear regression.

RESULTS

The majority of patients (97.5%) presented unilateral or bilateral UtA notches. The crude 5th, 50th, and 95th reference percentile curves of the UtA-PI at 1-34 days of the normal menstrual cycle were derived. In all curves, a progressive significant decrease occurred during the first 13 days, followed by an increase and recovery in the UtA-PI. The adjusted 5th, 50th, and 95th reference percentile curves for the effects of age and parity were also obtained. These two conditions generated an approximately identical UtA-PI pattern during the cycle, except with small but significant reductions at the temporal extremes.

CONCLUSIONS

The median, 5th, and the 95th percentiles of the UtA-PI decrease during the first third of the menstrual cycle and recover to their initial values during the last two thirds of the cycle. The rates of decrease and recovery depend significantly on age and parity.

Three-dimensional ultrasonographic placental volume in gestational diabetes mellitus

OBJECTIVES

We aimed to evaluate the placental volume and placental mean gray value in gestational diabetes mellitus (GDM) and healthy placentas using three-dimensional (3D) ultrasound and Virtual Organ Computer-aided AnaLysis (VOCAL).

METHODS

This case-control prospective study consisted of 39 singleton pregnancies complicated by GDM and 42 healthy singleton pregnancies matched for gestational age, maternal age and parity. Placental volume and placental volumetric mean gray values were evaluated. The placental volume (cm(3)) was analyzed using the VOCAL imaging analysis program and 3D histogram was used to calculate the volumetric mean gray value (%).

RESULTS

Placental volume was significantly larger in GDM (411.59 ± 170.82 versus 343.86 ± 128.94 cm(3); p = 0.046). There was no significant difference in mean gray value between GDM and healthy placentas (36.65 ± 7.02 versus 38.71 ± 7.91, respectively; p = 0.277). Placental volume was significantly correlated with gestational week (r = 0.219, p = 0.035) and parity (r = 0.228, p = 0.048). There was negative significant relation between placental volume and umbilical artery systolic/diastolic ratio, pulsatility index and resistance index (r = -0.278, p = 0.007; r = -0.315, p = 0.002; r = -0.322, p = 0.001, respectively).

CONCLUSIONS

Placental volume increases significantly in GDM, whereas mean gray values do not alter significantly. These data may reflect the placental changes in GDM placentas that may help to understand the pathophysiology better.

The association between parity and birthweight in a longitudinal consecutive pregnancy cohort

BACKGROUND

Nulliparity is associated with lower birthweight, but few studies have examined how within-mother changes in risk factors impact this association.

METHODS

We used longitudinal electronic medical record data from a hospital-based cohort of consecutive singleton live births from 2002-2010 in Utah. To reduce bias from unobserved pregnancies, primary analyses were limited to 9484 women who entered nulliparous from 2002-2004, with 23,380 pregnancies up to parity 3. Unrestricted secondary analyses used 101,225 pregnancies from 45,212 women with pregnancies up to parity 7. We calculated gestational age and sex-specific birthweight z-scores with nulliparas as the reference. Using linear mixed models, we estimated birthweight z-score by parity adjusting for pregnancy-specific sociodemographics, smoking, alcohol, prepregnancy body mass index, gestational weight gain, and medical conditions.

RESULTS

Compared with nulliparas', infants of primiparas were larger by 0.20 unadjusted z-score units [95% confidence interval (CI) 0.18, 0.22]; the adjusted increase was similar at 0.18 z-score units [95% CI 0.15, 0.20]. Birthweight continued to increase up to parity 3, but with a smaller difference (parity 3 vs. 0 β = 0.27 [95% CI 0.20, 0.34]). In the unrestricted secondary sample, there was significant departure in linearity from parity 1 to 7 (P < 0.001); birthweight increased only up to parity 4 (parity 4 vs. 0 β = 0.34 [95% CI 0.31, 0.37]).

CONCLUSIONS

The association between parity and birthweight was non-linear with the greatest increase observed between first- and second-born infants of the same mother. Adjustment for changes in weight or chronic diseases did not change the relationship between parity and birthweight.

Hemodynamic adaptations in different trimesters among nulliparous and multiparous pregnant women; the Generation R study

BACKGROUND

It has been suggested that maternal vascular adaptations during pregnancy differ between nulliparous and multiparous women. Therefore, we examined the associations of parity with blood pressure and hemodynamic placental function during pregnancy and risks of gestational hypertensive disorders.

METHODS

The study was embedded in a population-based prospective cohort study among 8,377 pregnant women. Information about parity and gravidity was obtained at enrollment. Blood pressure was repeatedly measured in each trimester and mean pulsatility and resistance indexes of uterine artery were measured in second and third trimesters. Information on gestational hypertension and preeclampsia was available from medical records.

RESULTS

As compared with nulliparous women, multiparous women had a lower systolic and diastolic blood pressure in each trimester of pregnancy and a slightly higher second and third trimester uterine artery resistance and pulsatility indexes (all P values < 0.05), but a lower risk of third trimester uterine artery notching (odds ratio (OR) 0.67 (95% confidence interval (CI):0.53, 0.84)). The risks of gestational hypertension and preeclampsia were lower among multiparous women as compared with nulliparous women (OR 0.32 (95% CI: 0.24, 0.43) and OR 0.24 (95% CI: 0.16, 0.37), respectively). Among multiparous women only, we did not observe associations of parity with hemodynamic parameters.

CONCLUSIONS

Nulliparous pregnant women have higher blood pressure levels throughout pregnancy and higher risks of notching and gestational hypertensive disorders. The first pregnancy might be a major risk factor for maternal hemodynamic maladaptations and vascular complications. Further studies are needed to explore the underlying mechanisms and consequences for fetal growth and development.

Associations of maternal psychological factors with umbilical and uterine blood flow

OBJECTIVE

Alteration to blood flow in the maternal-foetal compartment has been proposed as a mechanism underlying maternal psychological effects on pregnancy outcomes. This study characterised the progression of umbilical and uterine blood flow resistance in healthy pregnancies and evaluated concurrent and longitudinal associations with maternal anxiety and other psychological factors.

METHODS

The study assessed participants (n=107) at five visits spanning 24-38 weeks gestation. The resistance index (RI) in the uterine and umbilical arteries was measured with Doppler ultrasound. Maternal psychological function was assessed using validated, self-report instruments.

RESULTS

Hierarchical linear modelling revealed that uterine and umbilical RI decreased during the second half of gestation, and that uterine RI was lower in nulliparous women. Few concurrent associations emerged between psychological factors and RI. Longitudinal analyses determined that psychological well-being was associated with decreased left uterine artery RI, and psychological distress was associated with lower right artery RI.

CONCLUSIONS

Although uterine artery resistance was modestly associated with the maternal psychological milieu during gestation, our findings do not indicate an association between increased maternal distress and decreased RI. Thus, this study fails to affirm a key component of the hypothesised relation of maternal stress to foetal outcomes via vasoconstriction.

A prospective cohort study of the value of maternal plasma concentrations of angiogenic and anti-angiogenic factors in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia

OBJECTIVE

Changes in the maternal plasma concentrations of angiogenic (placental growth factor (PlGF) and vascular endothelial growth factor (VEGF)) and anti-angiogenic factors (sEng and vascular endothelial growth factor receptor-1 (sVEGFR-1)) precede the clinical presentation of preeclampsia. This study was conducted to examine the role of maternal plasma PlGF, sEng, and sVEGFR-1 concentrations in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia.

METHODS

This longitudinal cohort study included 1622 consecutive singleton pregnant women. Plasma samples were obtained in early pregnancy (6-15 weeks) and midtrimester (20-25 weeks). Maternal plasma PlGF, sEng, and sVEGFR-1 concentrations were determined using sensitive and specific immunoassays. The primary outcome was the development of preeclampsia. Secondary outcomes included term, preterm, and early-onset preeclampsia. Receiving operating characteristic curves, sensitivity, specificity, positive and negative likelihood ratios, and multivariable logistic regression were applied. A p-value of <0.05 was considered significant.

RESULTS

(1) The prevalence of preeclampsia, term, preterm, (<37 weeks) and early-onset preeclampsia (<34 weeks) was 3.8 (62/1622), 2.5 (40/1622), 1.4 (22/1622) and 0.6% (9/1622), respectively; (2) Higher likelihood ratios were provided by ratios of midtrimester plasma concentrations of PlGF, sEng, and sVEGFR-1 than single analytes; (3) Individual angiogenic and anti-angiogenic factors did not perform well in the identification of preeclampsia as a whole; in particular, they perform poorly in the prediction of term preeclampsia; (4) In contrast, a combination of these analytes such as the PlGF/sEng ratio, its delta and slope had the best predictive performance with a sensitivity of 100%, a specificity of 98-99%, and likelihood ratios for a positive test of 57.6, 55.6 and 89.6, respectively, for predicting early-onset preeclampsia.

CONCLUSIONS

(1) The PlGF/sEng ratio and its delta and slope had an excellent predictive performance for the prediction of early-onset preeclampsia, with very high likelihood ratios for a positive test result and very low likelihood ratios for a negative test result; and (2) Although the positive likelihood ratios are high and the positive predictive values low, the number of patients needed to be closely followed is 4:1 for the PlGF/sEng ratio and 3:1 for the slope of PlGF/sEng.

Platelet activation and endogenous thrombin potential in pre-eclampsia

INTRODUCTION

Platelets and the coagulation system may be involved in the pathogenesis of pre-eclampsia. We investigated whether platelet and coagulation activation markers, are elevated in pre-eclampsia.

MATERIALS/METHODS

Case-control study in which activated platelets, platelet-monocyte/ neutrophil aggregates, platelet microparticles (measured by flow cytometry) and four markers of thrombin generation capacity (endogenous thrombin potential (ETP), peak height, lag time and time to peak) using the Calibrated Automated Thrombogram system were assessed in pregnant women of similar gestational age with (n=46) and without (n=46) pre-eclampsia, and in healthy non-pregnant women (n=42).

RESULTS

The percentage of, CD62P+ platelets (p=0.013), CD62P+ platelet microparticles (p=0.029) and platelet-monocyte aggregates (p=0.019) were significantly higher in women with pre-eclampsia than the pregnant controls. Both groups of pregnant women had significantly higher ETP and peak height (p <0.001) than the healthy non pregnant group and the women with pre-eclampsia had significantly higher ETP and peak height (p<0.001) than the normotensive pregnant controls.

CONCLUSION

In the most comprehensive laboratory analysis to date, we found evidence of both platelet and coagulation activation in women with pre-eclampsia.

Gross placental structure in a low-risk population of singleton, term, first-born infants

Suboptimal fetal growth has been associated with an increased risk of adult disease, which may be exacerbated by an increased placental weight-to-fetal weight ratio. Placental weight is a summary measure of placental growth and development throughout pregnancy. However, measures of placental structure, including the chorionic disk surface area and thickness and eccentricity of the umbilical cord insertion, have been shown to account for additional variance in birth weight beyond that explained by placental weight. Little is known of the variability of these placental parameters in low-risk populations; their association with maternal, pregnancy, and neonatal characteristics; and the agreement between manual and digital measures. This study used manual and digital image analysis techniques to examine gross placental anatomy in 513 low-risk, singleton, term, first-born infants. Parametric methods compared groups and examined relationships among variables. Maternal birth weight, prepregnancy weight, and body mass index were associated with increased placental and birth weight (all P < 0.005), but only maternal birth weight was associated with increased placental surface area (P < 0.0005) and thickness (P = 0.005). Smoking during pregnancy reduced birth weight and increased the eccentricity of umbilical cord insertion (P = 0.012 and 0.034, respectively). The variability in these placental parameters was consistently lower than that reported in the literature, and correlations between digital and manual measurements were reasonable (r = .87-.71). Detailed analyses of gross placental structure can provide biologically relevant information regarding placental growth and development and, potentially, their consequences.

Lower uterine artery blood flow and higher endothelin relative to nitric oxide metabolite levels are associated with reductions in birth weight at high altitude

Reduced uteroplacental blood flow is hypothesized to play a key role in altitude-associated fetal growth restriction. It is unknown whether reduced blood flow is a cause or consequence of reduced fetal size. We asked whether determinants of uteroplacental blood flow were altered prior to reduced fetal growth and whether vasoactive and/or angiogenic factors were involved. Women residing at low (LA; 1,600 m, n = 18) or high altitude (HA; 3,100 m, n = 25) were studied during pregnancy (20, 30, and 36 wk) and 4 mo postpartum (PP) using Doppler ultrasound. In each study, endothelin (ET-1), nitric oxide metabolites (NO(x)), soluble fms-like tyrosine kinase (sFlt-1) and placental growth factor (PlGF) levels were quantified. At HA, birth weights were lower (P < 0.01) and small-for-gestational age was more common (P < 0.05) compared with LA. HA was associated with lower uterine artery (UA) diameter (P < 0.01) and blood flow (P < 0.05). Altitude did not affect ET-1, sFlt-1 or PlGF; however, ET-1/NO(x) was greater and NO(x) lower during pregnancy and PP at HA vs. LA. ET-1/NO(x) was negatively associated with birth weight (20 wk, P < 0.01; 36 wk, P = 0.05) at LA and HA combined. At HA, UA blood flow (30 wk) was positively associated with birth weight (dagger). UA blood flow and ET-1/NO(x) levels accounted for 45% (20 wk) and 32% (30 wk) of birth weight variation at LA and HA combined, primarily attributed to effects at HA. We concluded that elevated ET-1/NO(x) and altered determinants of uteroplacental blood flow occur prior to altitude-associated reductions in fetal growth, and therefore, they are likely a cause rather than a consequence of smaller fetal size.

Effects of maternal parity and late gestational nutrition on mRNA abundance for growth factors in the liver of postnatal sheep

The liver is a major metabolic and endocrine organ in growing neonates, but the extent to which its hormone receptor (R) sensitivity is potentially determined by maternal parity and the mother's nutritional environment is unknown. This was therefore investigated by sampling livers from postnatal sheep born to nulliparous or multiparous mothers. Offspring were sampled 1 or 30 days after birth from mothers consuming either 100 or 50% [i.e., nutrient-restricted (NR) group] of total metabolizable energy requirements from 110 days gestation to term (∼147 days). Regardless of maternal diet, offspring of nulliparous mothers were lighter at birth and had smaller livers. By 1 mo of age, they exhibited catch-up growth, an adaptation not seen when mothers were NR, but they retained their lighter livers. At both sampling ages, livers from offspring born to nulliparous mothers exhibited increased mRNA abundance for growth hormone (GH) receptor, IGF-IR, plus hepatocyte growth factor (HGF); and at day 1 only IGF-I, but not IGF-IIR mRNA was decreased. In addition, mRNA for IGF-II, the HGFR, c-Met, and Bax were persistently reduced in these offspring. Effects of parity were largely unaffected by maternal nutrient restriction. Maternal parity therefore has a substantial effect on liver size during postnatal development and its receptor population that is not dependent on maternal diet. First-born offspring appear to exhibit a resetting of the endocrine control of hepatic growth within the HGF and GH-IGF axis, which could have later consequences after their growth has caught up.

Uterine artery Doppler velocimetry at 11-14 weeks in singleton pregnancies conceived by assisted reproductive technology

OBJECTIVE

Singleton pregnancies resulting from assisted reproductive technologies (ART) have an increased risk of preterm delivery, pre-eclampsia and intrauterine growth restriction. The aim of the present study was to determine whether first-trimester trophoblastic invasion, as assessed by uterine artery Doppler velocimetry, is different in singleton pregnancies resulting from ART compared to those conceived naturally.

METHODS

Case-control study on 31 singleton ART pregnancies (26 in-vitro fertilization-embryo transfer, five intracytoplasmic sperm injection) and 62 matched pregnancies conceived spontaneously. Doppler velocimetry was performed at 11-14 weeks of gestation.

RESULTS

The mean resistance index (coefficient of variation) was 0.70 (17%) and 0.70 (18%) in ART and controls, respectively (P = 0.92). The corresponding values for mean pulsatility index were 1.40 (44%) and 1.47 (44%) in ART and controls, respectively (P = 0.58). Pregnancies with no, unilateral or bilateral diastolic notches were 48%, 26%, 26% and 36%, 37%, 27%, in ART and controls, respectively (P = 0.43).

CONCLUSION

There are no differences in uterine artery Doppler indices between pregnancies obtained by invasive ART and naturally conceived matched controls. This finding suggests that there is no major difference in trophoblastic invasion of the maternal spiral arteries between ART and spontaneous pregnancies.

Influence of parity on second-trimester uterine artery Doppler waveforms in twin pregnancy

We performed uterine artery Doppler velocimetry in 16 nulliparous and 16 parous women with non-preeclamptic singleton gestations and 16 nulliparous and 16 parous women with dichorionic twin gestations at 17-18 and 26-27 weeks of gestation. In both singleton and twin pregnancies, the average pulsatility index (PI) in nulliparous women was significantly higher than that in parous women at 17-18 weeks of gestation. At 26-27 weeks of gestation, however, there were no significant differences in PI between nulliparous and parous women with either singleton or twin pregnancies. During the early second-trimester of non-preeclamptic singleton and twin pregnancies, parity has a significant effect on uterine artery blood flow.

Influence of parity on first trimester endovascular trophoblast invasion

OBJECTIVE

To assess the effect of parity on endovascular trophoblastic invasion in early pregnancy.

DESIGN

Observational study.

SETTING

Teaching hospital.

PATIENT(S)

Healthy women at 10-14 weeks of gestation.

INTERVENTION(S)

Surgical termination of pregnancy for nonmedical reasons.

MAIN OUTCOME MEASURE(S)

Products of conception were blindly examined histologically with regard to the extent of decidual endovascular trophoblast invasion.

RESULT(S)

Samples were obtained from 20 nulliparous and 10 parous women. The presence of normal intradecidual endovascular trophoblast invasion was identified with a similar frequency in both groups (P=.28). However, the proportion of decidual vessels with endovascular trophoblast invasion was significantly higher in parous women (60%) compared with nulliparous women (32%, P<.001).

CONCLUSION(S)

Endovascular trophoblast invasion in early pregnancy is more extensive in parous women who already had an uncomplicated pregnancy than in nulliparous women.

Uterine artery Doppler screening for adverse pregnancy outcome

PURPOSE OF REVIEW

This article reviews publications in the area of uterine artery Doppler screening that were published during the past year.

RECENT FINDINGS

Studies have shown that assessment of a woman's level of risk for pre-eclampsia by uterine artery Doppler performs better than maternal history alone. Combination of maternal history and uterine artery Doppler findings leads to even more accurate assessment of risk, and allows calculation of patient-specific risk. Combining screening with uterine artery Doppler and maternal serum biochemical markers has been explored in some studies, but data remain limited and larger prospective longitudinal studies are needed to asses the effectiveness of these techniques. A number of promising markers for development of the disease have been identified, however, including pregnancy associated plasma protein-A, inhibin-A, activin-A and fibronectin, as well as placental growth factor, vascular endothelial growth factor and soluble fms-like tyrosine kinase 1.

SUMMARY

Uterine artery Doppler has proved useful in identifying women at high and low risk for developing complications of uteroplacental insufficiency and may aid in stratifying antenatal care. In addition, it can identify women in whom biochemical markers should be measured in order to develop screening tests and aid in evaluation of the pathophysiology of impaired placentation and pre-eclampsia. Whether pharmacological intervention in women identified to be at high risk for pre-eclampsia on the basis of Doppler is effective in reducing the incidence of the disease remains to be established.

Prediction and prevention of preeclampsia and IUGR

Preeclampsia, being one of the leading causes of maternal and perinatal morbidity and mortality, has been the subject of extensive research since its description. Preeclampsia has been called the disease of theories due to the enigma surrounding its exact pathophysiology. Despite the absence of treatment that reverses the disease process once started, screening for preeclampsia and intrauterine growth restriction (IUGR) has been a major clinical and research issue since the disease was first reported. This review evaluates the current evidence for prediction and prevention of preeclampsia and IUGR using clinical tests, maternal serum markers, and uterine artery Doppler screening. In addition, we critically evaluate the evidence regarding the different therapeutic strategies for the prevention of preeclampsia and IUGR and the latest clinical recommendations for their use.

Miscarriage in India: a population-based study

This study estimated birth order-specific miscarriage rates and characterized the influence of maternal age using the complete birth history of 90,303 ever-married women from the 1998-2000 Indian National Family Health Survey. Rates of miscarriage in India were low in association with early childbearing, whereas birth order as well as age substantially influenced miscarriage risk.

Second-trimester uterine artery Doppler and spontaneous preterm delivery

OBJECTIVE

To assess the relationship between second-trimester uterine artery (UtA) Doppler measurements and spontaneous preterm delivery.

METHODS

This was a retrospective analysis of UtA Doppler findings at 18-23 weeks' gestation in 234 singleton pregnancies with spontaneous preterm labor and 5472 pregnancies delivered at term. Cases with fetal chromosomal or structural abnormalities, pre-eclampsia, small-for-gestational-age (SGA) fetuses, concurrent maternal disease, cervical cerclage or history of cone biopsy were excluded.

RESULTS

UtA mean resistance index (RI) and number of protodiastolic notches were not significantly different in the spontaneous preterm labor group compared to the normal group. The 62 preterm deliveries not preceded by spontaneous preterm premature rupture of membranes (PPROM) showed a significantly higher RI and prevalence of bilateral notches than cases of preterm deliveries preceded by PPROM (n = 172). However, this difference was not confirmed in a logistic regression model.

CONCLUSION

Despite pathological evidence suggesting that defective placentation is associated with spontaneous preterm delivery, second-trimester UtA resistance, as assessed by Doppler ultrasound investigation, is not different in pregnancies subsequently complicated by preterm labor compared to pregnancies delivered at term.