Twin pregnancies conceived by assisted reproductive techniques: maternal and neonatal outcomes

Pregnancy outcomes of monochorionic diamniotic and dichorionic diamniotic twin pregnancies conceived by assisted reproductive technology and conceived naturally: a study based on chorionic comparison

OBJECTIVE

To evaluate monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin pregnancies conceived by assisted reproductive technology (ART) and conceived naturally.

METHODS

We retrospectively analyzed the data on twin pregnancies conceived by ART from January 2015 to January 2022,and compared pregnancy outcomes of MCDA and DCDA twins conceived by ART with those of MCDA and DCDA twins conceived naturally, pregnancy outcomes between MCDA and DCDA twins conceived by ART, and pregnancy outcomes of DCT and TCT pregnancies reduced to DCDA pregnancies with those of DCDA pregnancies conceived naturally.

RESULT

MCDA pregnancies conceived by ART accounted for 4.21% of the total pregnancies conceived by ART and 43.81% of the total MCDA pregnancies. DCDA pregnancies conceived by ART accounted for 95.79% of the total pregnancies conceived by ART and 93.26% of the total DCDA pregnancies. Women with MCDA pregnancies conceived by ART had a higher premature delivery rate, lower neonatal weights, a higher placenta previa rate, and a lower twin survival rate than those with MCDA pregnancies conceived naturally (all p < 0.05). Women with DCDA pregnancies conceived naturally had lower rates of preterm birth, higher neonatal weights, and higher twin survival rates than women with DCDA pregnancies conceived by ART and those with DCT and TCT pregnancies reduced to DCDA pregnancies (all p < 0.05).

CONCLUSION

Our study confirms that the pregnancy outcomes of MCDA pregnancies conceived by ART are worse than those of MCDA pregnancies conceived naturally. Similarly, the pregnancy outcomes of naturally-conceived DCDA pregnancies are better than those of DCDA pregnancies conceived by ART and DCT and TCT pregnancies reduced to DCDA pregnancies.

Maternal and perinatal outcomes in twin pregnancies following assisted reproduction: a systematic review and meta-analysis involving 802 462 pregnancies

BACKGROUND

ART is associated with higher rates of twin pregnancies than singleton pregnancies. Whether twin pregnancies conceived following ART have additional maternal and neonatal complications compared with non-ART twin pregnancies is not known.

OBJECTIVE AND RATIONALE

The objective was to quantify the risk of adverse maternal and perinatal outcomes among twin pregnancies conceived following ART compared with non-ART and natural conception. Existing reviews vary in the reported outcomes, with many studies including triplet pregnancies in the study population. Therefore, we aimed to perform an up-to-date review with an in-depth analysis of maternal and perinatal outcomes limited to twin pregnancies.

SEARCH METHODS

We searched electronic databases MEDLINE and EMBASE from January 1990 to May 2023 without language restrictions. All cohort studies reporting maternal and perinatal outcomes following ART compared with non-ART twin pregnancies and natural conception were included. Case-control studies, case reports, case series, animal studies, and in vitro studies were excluded. The Newcastle-Ottawa Scale was used to assess the methodological quality of the studies. Using random-effects meta-analysis, the estimates were pooled and the findings were reported as odds ratios (OR) with 95% CI.

OUTCOMES

We included 111 studies (802 462 pregnancies). Twin pregnancies conceived following ART were at higher risk of preterm birth at <34 weeks (OR 1.33, 95% CI 1.14-1.56, 29 studies, I2 = 73%), <37 weeks (OR 1.26, 95% CI 1.19-1.33, 70 studies, I2 = 76%), hypertensive disorders in pregnancy (OR 1.29, 95% CI 1.14-1.46, 59 studies, I2 = 87%), gestational diabetes mellitus (OR 1.61, 95% CI 1.48-1.75, 51 studies, I2 = 65%), and caesarean delivery (OR 1.80, 95% CI 1.65-1.97, 70 studies, I2 = 89%) compared with non-ART twins. The risks for the above maternal outcomes were also increased in the ART group compared with natural conception. Of the perinatal outcomes, ART twins were at significantly increased risk of congenital malformations (OR 1.17, 95% CI 1.05-1.30, 39 studies, I2 = 59%), birthweight discordance (>25% (OR 1.31, 95% CI 1.05-1.63, 7 studies, I2 = 0%)), respiratory distress syndrome (OR 1.32, 95% CI 1.09-1.60, 16 studies, I2 = 61%), and neonatal intensive care unit admission (OR 1.24, 95% CI 1.14-1.35, 32 studies, I2 = 87%) compared with non-ART twins. When comparing ART with natural conception, the risk of respiratory distress syndrome, intensive care admissions, and birthweight discordance >25% was higher among the ART group. Perinatal complications, such as stillbirth (OR 0.83, 95% CI 0.70-0.99, 33 studies, I2 = 49%), small for gestational age <10th centile (OR 0.90, 95% CI 0.85-0.95, 26 studies, I2 = 36%), and twin-twin transfusion syndrome (OR 0.45, 95% CI 0.25-0.82, 9 studies, I2 = 25%), were reduced in twin pregnancies conceived with ART versus those without ART. The above perinatal complications were also fewer amongst the ART group than natural conception.

WIDER IMPLICATIONS

ART twin pregnancies are associated with higher maternal complications than non-ART pregnancies and natural conception, with varied perinatal outcomes. Women seeking ART should be counselled about the increased risks of ART twin pregnancies and should be closely monitored in pregnancy for complications. We recommend exercising caution when interpreting the study findings owing to the study's limitations.

Neonatal condition at birth of twins conceived by medically assisted reproductive technology compared to those conceived spontaneously: A retrospective study

OBJECTIVE

To examine neonatal outcomes at birth among twins conceived spontaneously or by medically assisted reproduction (MAR).

METHODS

A retrospective study was conducted at a single university teaching hospital on data collected between January 1995 and September 2019. Live twin deliveries at more than 24 weeks of pregnancy were included. The study group consisted of women who conceived by MAR and the controls were spontaneously conceived twins. The study group was further divided into two groups: in vitro fertilization (IVF) and ovulation induction (OI) groups. The primary outcomes were umbilical artery pH less than 7.1 and/or Apgar score less than 7 of any twin 5 min after birth.

RESULTS

Overall, 2235 eligible twin gestations were included, corresponding to a total of 4470 live neonates; 1009 (45.1%) conceived by MAR (762 [75.5%] IVF and 247 [24.5%] OI) and 1226 (54.9%) conceived spontaneously. Incidence of the primary outcome was 5.3% and 5.1% in the study and control groups, respectively (P = 0.71). The primary outcome was comparable among the IVF (5%), OI (6.2%), and control (5.1%) groups. The results did not change even after adjusting for demographic and obstetric variables, including mode of delivery, which differed between the groups.

CONCLUSION

Neonatal condition of twin pregnancies at birth among MAR subgroups is similar to spontaneously conceived twins.

Gestational age at delivery of twins and perinatal outcomes: a cohort study in Aberdeen, Scotland

Background: Twin pregnancy is associated with a threefold increase in perinatal death compared to singletons.  The objective of this study was to determine the risk of perinatal death in twins by week of gestation and to quantify the effect of known risk factors. Methods: A cohort analysis was performed using data from the Aberdeen Maternity and Neonatal Databank (AMND).  The exposure was gestational age at delivery and the primary outcome was perinatal death.  Adjusted hazard ratios (aHRs) for perinatal death according to gestational age at delivery were determined by multivariate Cox proportional hazards regression modelling with robust standard errors to account for clustering in the twin infants.  Confounders and risk factors quantified and adjusted for in the model included maternal age, smoking, parity, marital status and year of birth.  Kaplan-Meier time to event analysis was used to determine the differences in survival according to chorionicity and assisted reproduction technologies (ART) conception status. Results: The population comprised of 7,420 twin babies born between 1950 and 2013 in the Grampian area of Northern Scotland.  There were 272 stillbirths in the cohort (3.67%) and 273 neonatal deaths (3.68%). Compared to delivery at 37-38 weeks, delivery before 37 weeks was associated with a 2-fold increase in perinatal death. Monochorionic twins had a 2-fold increase in perinatal death compared to dichorionic twins (aHR 2.15, 95% CI 1.60-2.90). Twins conceived by ART did not have a greater risk of perinatal death compared to those naturally conceived (aHR 1.21, 95% CI 0.87-1.68) Conclusion:  This study suggests that delivery of twins at 37-38 weeks is associated with the lowest risk of perinatal death.

Gestational age at delivery of twins and perinatal outcomes: a cohort study in Aberdeen, Scotland

Background: Twin pregnancy is associated with a threefold increase in perinatal death compared to singletons.  The objective of this study was to determine the risk of perinatal death in twins by week of gestation and to quantify the effect of known risk factors. Methods: A cohort analysis was performed using data from the Aberdeen Maternity and Neonatal Databank (AMND).  The exposure was gestational age at delivery and the primary outcome was perinatal death.  Adjusted hazard ratios (aHRs) for perinatal death according to gestational age at delivery were determined by multivariate Cox proportional hazards regression modelling with robust standard errors to account for clustering in the twin infants.  Confounders and risk factors quantified and adjusted for in the model included maternal age, smoking, parity, marital status and year of birth.  Kaplan-Meier time to event analysis was used to determine the differences in survival according to chorionicity and assisted reproduction technologies (ART) conception status. Results: The population comprised of 7,420 twin babies born between 1950 and 2013 in the Grampian area of Northern Scotland.  There were 272 stillbirths in the cohort (3.67%) and 273 neonatal deaths (3.68%). Compared to delivery at 37-38 weeks, delivery at or beyond 39 weeks was associated with a significant increase in perinatal death (aHR 2.00 [95% CI 1.45-2.78]).  Monochorionic twins had a 2-fold increase in perinatal death compared to dichorionic twins (aHR 2.15, 95% CI 1.60-2.90). Twins conceived by ART did not have a greater risk of perinatal death compared to those naturally conceived (aHR 1.21, 95% CI 0.87-1.68) Conclusion:  This study suggests that delivery of twins at 37-38 weeks is associated with the lowest risk of perinatal death.

Dizygotic twin pregnancies after medically assisted reproduction and after natural conception: maternal and perinatal outcomes

OBJECTIVE

To compare maternal and perinatal outcomes in dizygotic twin pregnancies conceived after medically assisted reproduction (MAR) with outcomes after natural conception (NC).

DESIGN

Nationwide registry based study.

SETTING

Academic medical center.

PATIENT(S)

Primiparous women who delivered opposite sex twins between January 2000 and December 2012 in the Netherlands, comprising dizygotic twin pregnancies: 6,694 women, 470 after ovulation induction (OI), 511 after intrauterine insemination with controlled ovarian hyperstimulation (IUI-COH), 2,437 after in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI), and 3,276 after NC.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Multivariable logistic regression and generalized linear mixed models to evaluate differences in outcomes: maternal outcomes of hypertension, preeclampsia, preterm delivery, hemorrhage, and delivery mode, perinatal outcomes including small for gestational age (SGA) with birth weight <10th percentile, birth weight <1,500 g, 5-minute Apgar score <7, admission to neonatal intensive care unit, congenital anomalies, and perinatal mortality.

RESULT(S)

We found no statistically significant differences in maternal or perinatal outcomes after OI compared with NC. Women pregnant after IVF-ICSI had a lower risk for hypertension (adjusted odds ratio [aOR] 0.74; 95% confidence interval [CI], 0.66-0.83) compared with women pregnant after NC. After IUI-COH more children had Apgar scores <7 (adjusted odds ratio (aOR) 1.38; 95% confidence interval (CI) 1.05-1.81) and perinatal mortality rates were higher (aOR 1.56; 95% CI, 1.04-2.33) compared with NC. We found no differences in perinatal outcomes after IVF-ICSI compared with NC.

CONCLUSION(S)

Overall, maternal and perinatal risks other than those due to multiplicity are similar for twin pregnancies conceived after MAR and after NC.

Multifetal gestations with assisted reproductive technique before the single-embryo transfer legislation: obstetric, neonatal outcomes and congenital anomalies

OBJECTIVE

To compare perinatal, neonatal outcome and congenital anomalies of multiple gestations conceived by means of assisted reproductive techniques with spontaneously conceived multiples before the limitation of number of embryo transfer.

METHODS

Cases consisted of assisted reproductive technique (ART) multifetal gestations and control group comprised of spontaneously conceived multifetal gestations delivered in the same time period. Outcomes were perinatal, neonatal outcome, long-term outcomes and congenital anomalies of multiple gestations. There were 270 multifetal pregnancies for analysis, of which 137 were achieved by ART and 133 were spontaneous in this prospective study.

RESULTS

Incidences of preeclampsia, gestational diabetes, deep vein thrombosis, thrombocytopenia, intrahepatic cholestasis and preterm premature rupture of membranes were similar in ART and spontaneous groups. There was no difference in fetal malformation rates between ART and control group, but higher rates of central nervous system malformation were observed (4 (1.5%) in control, 0 in ART group, p = 0.04) in spontaneous group. No difference was seen in the perinatal mortality.

CONCLUSIONS

Neonatal and maternal outcomes are comparable between ART and spontaneous multifetal gestations. Congenital fetal malformation rates between ART and spontaneous multifetal pregnancies were similar except central nervous system malformation that was more likely in spontaneously conceived ones.

Multiple pregnancies following assisted reproductive technologies--a happy consequence or double trouble?

The association between assisted reproduction technologies (ART) and multiple pregnancy is well-established, with a multiple birth rate of 24% in ART pregnancies. Multiple pregnancy is associated with significantly increased maternal and perinatal morbidity and mortality, as well as increased costs to the National Health Service. Evidence relating to the obstetric outcomes of ART twins versus naturally conceived twins is discussed in this review. Methods to reduce the risk of multiple births including elective single embryo transfer and multifetal pregnancy reduction are also discussed.

Predicting personalized multiple birth risks after in vitro fertilization-double embryo transfer

OBJECTIVE

To report and evaluate the performance and utility of an approach to predicting IVF-double embryo transfer (DET) multiple birth risks that is evidence-based, clinic-specific, and considers each patient's clinical profile.

DESIGN

Retrospective prediction modeling.

SETTING

An outpatient university-affiliated IVF clinic.

PATIENT(S)

We used boosted tree methods to analyze 2,413 independent IVF-DET treatment cycles that resulted in live births. The IVF cycles were retrieved from a database that comprised more than 33,000 IVF cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The performance of this prediction model, MBP-BIVF, was validated by an independent data set, to evaluate predictive power, discrimination, dynamic range, and reclassification.

RESULT(S)

Multiple birth probabilities ranging from 11.8% to 54.8% were predicted by the model and were significantly different from control predictions in more than half of the patients. The prediction model showed an improvement of 146% in predictive power and 16.0% in discrimination over control. The population standard error was 1.8%.

CONCLUSION(S)

We showed that IVF patients have inherently different risks of multiple birth, even when DET is specified, and this risk can be predicted before ET. The use of clinic-specific prediction models provides an evidence-based and personalized method to counsel patients.

Obstetric and Perinatal Outcomes of Dichorionic Twin Pregnancies According to Methods of Conception: Spontaneous Versus In-Vitro Fertilization

We have observed the inconsistent findings from various studies on twin pregnancy outcomes obtained by assisted reproductive technology and spontaneous conception. In most studies, however, the concrete chorionicity, regarded as a confounding factor for predicting the perinatal outcomes of twin pregnancies, has not been determined. The purpose of this study was to compare obstetric and perinatal outcomes of only the dichorionic twin pregnancies according to the methods of conception: spontaneous and in-vitro fertilization (IVF). The twin pairs with dichorionicity reported from 1995 to 2008 were investigated and we divided them into two groups which consisted of 286 and 134 twins by spontaneous conception and IVF, respectively. Odds ratios for associations between IVF and pregnancy outcomes were analyzed after adjustment for maternal age and parity. There were no risk differences between the two groups regarding the obstetric complications, which include preterm delivery, preterm labor, preterm premature rupture of membranes, preeclampsia, placenta previa, and abruption. Any differences were not shown in the two groups for the risk estimates of perinatal outcomes, such as low birthweight, very low birthweight, small for gestational age, Apgar scores of < 7 at 5 minutes, discordance in birthweights, congenital anomalies and mortality. However, twins conceived after IVF were less likely to be admitted to the neonatal intensive care unit than those conceived spontaneously (adjusted OR 0.488; 95% confidence interval 0.261–0.910). In the cases of dichorionic twins, IVF may not be associated with adverse perinatal and obstetric outcomes compared with spontaneous conception.

Outcome of twin pregnancies conceived after assisted reproductive techniques

CONTEXT:

There is a continuous controversy regarding the obstetric perinatal outcome of twin pregnancies conceived after assisted reproductive techniques (ART). There is an ongoing discussion whether theses parameters may show poorer results as compared to spontaneous conception.

AIMS:

To evaluate the outcome of multifetal pregnancies and to compare maternal and neonatal complications between spontaneously conceived and assisted reproductive therapy.

SETTINGS AND DESIGN:

Prospective case-control study.

MATERIALS AND METHODS:

In this prospective case-control study of 2-year duration, obstetric and perinatal outcomes were compared in 36 ART twin pregnancies (Group A) with 138 twins who conceived naturally (Group B). The outcomes were analyzed and used for a comparison between spontaneous and assisted multifetal pregnancies.

STATISTICAL ANALYSIS:

The continuous variables were analyzed by Student's t-test and categorical variables were analyzed with Fisher's exact test.

RESULTS:

Pregnancy-related complications like pregnancy-induced hypertension, antepartum hemorrhage, were similar in both groups. Incidence of cesarean section, preterm delivery, and hospital stay was significantly more in Group A vs. Group B, P < 0.001. The newborns in the assisted group had more complications than the spontaneous group; most notable were respiratory distress syndrome, newborn intensive care admission, sepsis, and longer hospital stay (4.8 days vs. 1.6 days, P < 0.001).

CONCLUSIONS:

Increased rates of cesarean section and preterm delivery are the main reasons for increased obstetric risk in pregnancies conceived through ART. Preterm birth and neonatal prematurity-related complications were the main cause for longer stay in hospital in ART-conceived twins.

Comparison of obstetric outcomes in twin pregnancies after in vitro fertilization, ovarian stimulation and spontaneous conception

OBJECTIVE

To compare the outcomes of liveborn twin gestations conceived after in vitro fertilization (IVF) or ovarian stimulation with spontaneously conceived twin pregnancies.

METHODS

A review of all twin gestations delivered at Winthrop-University Hospital from 1 January 1999 to 31 December 2000. Women who underwent fetal reduction or had a demise of one twin were excluded. Maternal demographics, antepartum complications, mode of delivery and perinatal outcome were compared.

RESULTS

Sixty pregnancies were conceived after IVF, 34 were conceived by ovarian stimulation and 101 were spontaneously conceived. Women in the IVF group were older (p < 0.001), were more often 35 years or older (p < 0.001) and primiparous (p = 0.005). More women in the ovarian stimulation group had a poor obstetric history (p = 0.04). Spontaneous gestations had a higher incidence of monochorionic placentations (p = 0.002). There were no differences in gestational age at delivery, antepartum complications, or mode of delivery. There were fewer low-birth-weight neonates in the IVF group (odds ratio 0.59, 95% confidence interval 0.35-0.98; p = 0.03) than in the spontaneous group, but the difference disappeared when only the dichorionic pregnancies were compared. Other neonatal outcomes studied were the same among groups.

CONCLUSION

Twin gestations conceived following IVF and ovarian stimulation appear to have similar outcomes to spontaneously conceived twin gestations.

Neonatal outcomes in triplet pregnancies: assisted reproduction versus spontaneous conception

AIMS

The purpose of this study is to compare neonatal outcomes of spontaneously conceived triplets with triplets conceived by assisted reproduction.

METHODS

This was a retrospective cohort study of all cases from assisted triplet pregnancies and controls from spontaneous triplet pregnancies. A total of 24 triplet pregnancies were studied: six spontaneous and 18 assisted. The following variables were evaluated in all newborns: prematurity, birth-weight, small for gestational age, birth-weight discordance, Apgar scores, major neonatal morbidity and perinatal mortality.

RESULTS

Gestational age (33+/-1 vs. 33+/-2 weeks) and birth-weight (1760+/-256 vs. 1907+/-452 g) were similar in spontaneous and assisted triplet pregnancies. There were no significant differences in the rates of small for gestational age, discordance, and major neonatal morbidity. In the assisted reproduction group only the following cases were recorded: 1 surgically treated patent ductus arteriosus, 1 feto-fetal transfusion syndrome, 2 grade II intraventricular hemorrhage, 1 Cri du Chat syndrome and 1 stillbirth with malformations.

CONCLUSIONS

This study is unable to assess the influence of assisted reproduction on the neonatal outcomes of triplet pregnancies. However, the results suggest that the incidence of major neonatal morbidity, especially malformations, might increase due to assisted reproduction. This finding requires further confirmation.

A retrospective analysis of placentas from twin pregnancies derived from assisted reproductive technology

There are conflicting studies associating twin pregnancies derived from assisted reproductive technology (ART) with preterm birth, low birthweight, and other negative outcomes. This work investigates whether ART is linked with any placental pathology, given that placentation significantly influences fetal development. A 5-year, retrospective cohort study was conducted on placentas from twin pregnancies. The placental information from 417 patients was divided into two groups: placentas derived from ART and placentas derived from spontaneous pregnancies (non-ART). Available clinical information and pathologic findings from both groups then were compared. There was no statistical difference in the prevalence of placental pathology between the non-ART and ART cohorts (i.e., cord insertion, single umbilical artery, cord knot, retroplacental hemorrhage, infarction, vasculopathy, vascular anastomoses, chorangiosis, villitis, deciduitis, chorioamnionitis, meconium staining). However, 8% of ART multiple pregnancies were monochorionic. While monochorionicity is a known risk factor for adverse obstetric and neonatal outcomes, the rate of monochorionic placentation did not increase as a result of ART. Nevertheless, it is interesting to note that this small percentage of monochorionic placentation occurred in the ART cohort despite the implantation of individual embryos. Overall, the data suggests that ART does not have a role in the pathologic placentation of twin pregnancies.

Obstetric outcome of twin pregnancies conceived by in vitro fertilization and ovulation induction compared with those conceived spontaneously

OBJECTIVE

To compare the obstetric characteristics of twin pregnancies conceived by in vitro fertilization (IVF) and ovulation induction with those conceived spontaneously.

DESIGN

Case control study.

SETTING

Tertiary Medical Center.

PATIENTS

All twin deliveries that were achieved by IVF (n=558) and ovulation induction (n=478) from January 1988 through December 2002 were evaluated. Each group was compared with a control group that conceived spontaneously (n=3694) and was delivered during the same period.

INTERVENTIONS

Ovulation induction, IVF-ET.

MAIN OUTCOME MEASURES

Obstetrical complications.

RESULTS

Multivariate analysis showed that patients who conceived with the assistance of IVF and ovulation induction had a significantly higher risk for gestational diabetes mellitus (odds ratio [OR]=2.41, 95% confidence interval [CI]=1.77-3.29 and OR=1.71, CI=1.2-2.42, respectively), cesarean section (OR=2.17, 95% CI=1.74-2.70 and OR=1.76, CI=1.43-2.16, respectively), and a lower gestational age at birth in the IVF group (OR=0.91, 95% CI=0.88-0.94), compared with their controls.

CONCLUSIONS

After controlling for maternal age, and nulliparity we demonstrated that twin pregnancies conceived with the assistance of IVF and ovulation induction are at increased risk for gestational diabetes mellitus, and delivery by cesarean section. In addition, IVF conceived pregnancies have a lower gestational age at birth.

Gestational hypertension in pregnancies supported by infertility treatments: role of infertility, treatments, and multiple gestations

OBJECTIVE

To investigate the association between infertility treatments and gestational hypertension and preeclampsia.

DESIGN

Retrospective observational cohort.

SETTING

General population, United States and Canada.

PATIENT(S)

Five thousand one hundred fifty-one women with non-malformed infants participating in the Slone Epidemiology Center Birth Defects Study between 1998 and 2006.

INTERVENTION(S)

Women were interviewed within 6 months after delivery about sociodemographic and medical factors, about the onset of gestational hypertension and preeclampsia, and about infertility treatments.

MAIN OUTCOME MEASURE(S)

We estimated relative risks and 95% confidence intervals by using unconditional logistic regression.

RESULT(S)

The incidence of gestational hypertension was 8.9% (423/4,762) among women without infertility treatments and was 15.8% (55/349) among women undergoing infertility treatments. Compared with spontaneous pregnancies, the crude relative risk for gestational hypertension in pregnancies resulting from infertility treatments was 1.9 (95% confidence interval, 1.4-2.6). Multivariate adjustment for parity and prepregnancy body mass index resulted in a relative risk of 1.6 (1.1-2.1). Further adjustment for multiple pregnancies, or restriction of the analyses to singleton pregnancies, moved the relative risk to 1.3. Each specific infertility procedure or drug was associated with a similarly elevated risk, which disappeared after adjustment for multiple gestations. Results were similar for preeclampsia.

CONCLUSION(S)

Pregnancies resulting from infertility treatments have a higher incidence of gestational hypertension and preeclampsia than do spontaneous conceptions. This increased risk is largely explained by the higher frequency of multiple gestations.

Outcomes of multifetal pregnancies

AIM

To determine the outcomes of multifetal pregnancies and to compare maternal and neonatal complications between spontaneously conceived and assisted reproductive therapy.

METHODS

A retrospective analysis was conducted of the information from medical records relating to all multifetal pregnancies. The outcomes were analyzed and used for a comparison between spontaneous and assisted multifetal pregnancies.

RESULTS

There were 387 multifetal pregnancies during the study period, which was 1.3% of all the deliveries; 334 cases (86.3%) were spontaneous conceptions and 53 cases (13.7%) were the result of assisted reproductive therapy. Higher-order fetuses (> or =3) represented 8% of all multifetal pregnancies, 13% in the spontaneous group and 87% in the assisted group. The overall cesarean delivery rate was 73.9%. The assisted reproductive therapy group had a cesarean rate of 90.6% compared with 71.3% in the spontaneous group (P = 0.008). The assisted multifetal pregnancy group had more preterm labors and a longer maternal hospital stay than the spontaneous group. One maternal death occurred in the assisted group. The main causes of early neonatal death were prematurity, infection and congenital malformation. The newborns in the assisted group had more complications than the spontaneous group; most notable were respiratory distress syndrome, newborn intensive care admission, infection and longer hospital stay (6 days vs 15 days, P < 0.001). More complications occurred in higher-order fetuses than with twins.

CONCLUSIONS

Assisted multifetal pregnancies were more likely to be delivered by cesarean section and had a higher rate of higher-order fetuses, preterm birth and neonatal prematurity-related complications with a longer hospital stay in both mothers and newborns, than spontaneous multifetal pregnancies.

Perinatal outcomes of spontaneous twins compared with twins conceived through intracytoplasmic sperm injection

OBJECTIVE

To compare perinatal outcomes in spontaneous twins compared with those conceived by intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective case-control study.

PATIENTS

Cases consisted of 274 intracytoplasmic sperm injection twins, controls were 348 naturally conceived twins delivered between 1999 and 2003 in a tertiary hospital.

MAIN OUTCOME MEASURES

Birth weight, gestational age at birth, cesarean delivery rate, perinatal mortality and morbidity, congenital anomalies, gestational diabetes and pregnancy induced hypertension.

RESULTS

Preterm deliveries (76.6% vs. 64.1% <37 weeks and 19.7% vs. 13.2% <32 weeks) and low birth weight (73% vs. 60.3% <2500 g and 19.7% vs. 12.6% <1500 g) were significantly higher in the ICSI group compared with controls. Gestational diabetes mellitus (8% vs. 2.9%) and cesarean deliveries (95.2% vs. 77.6%) were more common in cases compared with the control group. There was a significantly higher rate of perinatal morbidity (16.4% vs. 7.8%) and mortality (8% vs. 2.6%) in ICSI twins. The incidence of congenital malformations diagnosed at birth was higher in cases (4.4%) compared with controls (0.9%) but the difference was not significant when adjusted for maternal age.

CONCLUSION

Perinatal outcomes of twins after ICSI treatment are less optimal than naturally conceived twins.

Birthweight of singletons after assisted reproduction is higher after single- than after double-embryo transfer

BACKGROUND

Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET).

METHODS

We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child.

RESULTS

Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 +/-617.5 g versus 3324.6+/-509.7 g , P<0.01). Also preterm birth (<37 weeks) [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.06-2.94] and low birthweight (<2500 g) (OR 3.38, 95% CI 1.86-6.12) are significantly more common in DET singletons.

CONCLUSIONS

Singleton birth after SET is advantageous compared with DET. This sheds new light on the reasons why singleton births following ART do worse than spontaneously conceived singletons in IVF programs, where double- or multiple-embryo transfer is standard.

Abnormal placental cord insertion may induce intrauterine growth restriction in IVF-twin pregnancies

BACKGROUND

This study determined whether twins conceived through assisted reproduction technology (ART) have an increased risk of perinatal complications compared with natural twin pregnancies and investigated potential associated major risk factors.

METHODS

This retrospective study consisted of 199 twins born between 1994 and 2003. There were four groups according to conception modalities: 97 twins after spontaneous pregnancy, 24 after induced ovulation, 28 after intrauterine insemination (IUI) and 50 after IVF with embryo transfer. Analysis included preterm birth, Caesarean delivery, weight discordance, intrauterine growth restriction (IUGR), low-birth-weight, Apgar score, chorionicity, gross placental pathology and placental umbilical cord insertion (UCI) site.

RESULTS

A significant difference was found in IUGR between the IVF group (7.0%) and spontaneous pregnancy group (14.9%). When maternal age was >30 years there was a 2.86-fold increase in the risk of IUGR. There was a 3.69-fold increased risk of IUGR in the presence of abnormal UCI (odds ratio 3.69, 95% CI 1.62-8.42) and a 2.18-fold increased risk of abnormal UCI in monochorionic twins when compared with dichorionic twins (odds ratio 2.18, 95% CI 1.30-3.66).

CONCLUSION

Twins conceived through ART are not at an increased risk of perinatal complications. A relationship has been found between abnormal UCI and IUGR.

Is there increased monozygotic twinning after assisted reproductive technology?

Over the past two decades there has been an association between assisted reproductive technologies and increased monozygotic twinning. The association is not clear nor are the causes of assisted reproductive technology-related monozygotic twinning understood, although there are several theories as to the possible mechanisms involved. This review looks at some of the assisted reproductive technologies which may be associated with an increased risk of monozygotic twinning such as intracytoplasmic sperm injection, assisted hatching and blastocyst transfers. Determining the true incidence of monozygotic twinning after assisted reproductive technologies is important as there is a well-documented increase in perinatal morbidity and mortality of monozygotic twins compared to singleton and dizygotic pregnancies.

Twin gestation in older women: antepartum, intrapartum complications, and perinatal outcomes

OBJECTIVE

The aim of this study is to present pregnancy and perinatal outcomes of twin gestations in older women and compare them with that for younger women.

STUDY DESIGN

We conducted a retrospective cohort study of twin pregnancies in our department between 1988 and 2003. The women were classified into two groups by maternal age: women of age 35 years and older (study group) and women less than 35 years (control group). Population characteristics, complications during pregnancy and delivery, and neonatal outcomes were assessed. The Student's t-test, chi2 test, Fisher exact test, and binary logistic regression analysis were used to examine the relationship between maternal age and the different variables.

RESULTS

A total of 238 twin pregnancies were enrolled (study group, 57 women; control group, 181 women). Spontaneous conceptions were significantly higher in the control group (P < 0.001), while conceptions after in vitro fertilization (IVF) were significantly higher in study group (P < 0.001). Mean figures of gestational age at delivery and birth weight for the older group did not differ significantly from the younger group. Although the antepartum and intrapartum complications were more common in the study group, they were not statistically significant compared to the control group. This was also true for the perinatal outcomes. Only the very low birth weight (VLBW < 1,500 g) rate was significantly higher in the study group. The number of perinatal deaths was similar on comparison by maternal age.

CONCLUSIONS

Based on our study, advanced maternal age at twin gestation does not seem to affect significantly pregnancy complications and perinatal outcomes. VLBW was the only unfavorable perinatal outcome related to advanced maternal age.

Grossesses gémellaires après AMP

From 1986 to 2002, 16,618 twin babies have been reported to FIVNAT. Mean length of gestation was 36.74 weeks. The mean weight was 2413 g and mean height 46 cm. The proportion of prematurity under 28 weeks of amenorrhea was 1.17% and under 33 weeks: 7.78%. These data are similar to those reported in the French AUDIPOG Report.

IVF/ICSI twin pregnancies: risks and prevention

Since the 1970s, the national twin birth rates have been increasing worldwide. Apart from the increasing childbearing age, the main cause is the use of assisted reproductive technologies (ART). To explore the overall consequences of dual embryo transfer (DET), the literature has been reviewed systematically regarding short- and long-term outcomes of IVF/ICSI twin pregnancies i.e. pregnancy complications, maternal risks, obstetric outcome and long-term morbidity including neurological sequelae, cognitive development and family implications. Another consequence of DET is vanishing twins, which seems to be a possible cause of adverse outcome in IVF singletons. The sparse literature on vanishing twins in IVF pregnancies and the influence on the surviving co-twin were also addressed. Finally, to determine the effects of implementing elective single embryo transfer (eSET), trials concerning eSET versus DET were analysed. In the light of the steadily increasing twin birth rates and the findings in this overview, where IVF/ICSI twins carry adverse outcome, it should be emphasized that the major obstacle in IVF remains the high twin birth rate. Furthermore vanishing twins account for another hazard of DET. These problems can be resolved by implementing eSET, diminishing the twin birth rate without affecting the overall goal of achieving a healthy infant.

Nutrition in multiple gestations

Multiple pregnancies represent a state of magnified nutritional requirements, resulting in a greater nutrient drain on maternal resources and an accelerated depletion of nutritional reserves. Maternal weight gain to 20 weeks and between 20 and 28 weeks has the greatest effect on birthweight in twin and triplet pregnancies, particularly among underweight women. Parity, which most likely represents a higher proportion of body fat, has a positive effect on pregnancy outcome, with an average 7 to 10 days longer gestation for multiparous versus nulliparous women. In addition to being the nutrients most often lacking in a woman's diet, calcium, magnesium, and zinc have been identified as having the most potential for reducing pregnancy complications and improving outcomes.

Comparison of outcome of pregnancy after intra-uterine insemination (IUI) and IVF

INTRODUCTION

Pregnancy outcome after IVF has been shown to be worse than after spontaneous conception. There is discussion as to whether this results from the technique itself or the patient characteristics. This study compares pregnancy outcome after IVF and intra-uterine inemination (IUI) in a matched patient group.

METHODS

Data were obtained from our IVF and IUI databases (1997-2001). Matching was performed for maternal age, parity and plurality, and 126 IUI pregnancies were compared with 126 IVF pregnancies. Outcome variables were pregnancy duration, birth weight, Caesarean section rates, preterm contraction rates, neonatal intensive care unit admission, Apgar score, blood loss rates and maternal hypertension.

RESULTS

None of the analysed parameters was statistically different between the groups.

CONCLUSION

This matched case-control study does not show different pregnancy outcomes after IVF and IUI. Since there is no reason to believe that the IUI technique in itself leads to an increased obstetric or neonatal risk, this study suggests that the worse pregnancy outcome after IVF as compared with spontaneous conceptions is due to the specific patient characteristics, rather than to the use of IVF itself.

Multiple gestation and infertility treatment: registration, reflection and reaction—the Belgian project

Multiple pregnancies associated with infertility treatment are recognized as an adverse outcome and are responsible for morbidity and mortality related to prematurity and very low birthweight population. Due to the epidemic of iatrogenic multiple births, the incidence of maternal, perinatal and childhood morbidity and mortality has increased. This results in a hidden healthcare cost of infertility therapy and this may lead to social and political concern. Reducing the number of embryos transferred and the use of natural cycle IVF will surely decrease the number of multiple gestations. Consequently, optimized cryopreservation programmes will be essential. For non-IVF hormonal stimulation, responsible for more than one-third of all multiple pregnancies after infertility treatment, a strict ovarian stimulation protocol aiming at mono-ovulation is crucial. Multifetal pregnancy reduction is an effective method to reduce high order multiplets but carries its own risk of medical and emotional complications. Excellent data collection of all infertility treatments is needed in our discussion with policy makers. The Belgian project, in which reimbursement of assisted reproduction technology-related laboratory activities is linked to a transfer policy aiming at substantial multiple pregnancy reduction, is a good example of cost-efficient health care through responsible, well considered clinical practice.

Fetal programming: the perspective of single and twin pregnancies

Multiple pregnancy is associated with increased risk of adverse consequences for both mother and fetus(es), including increased rates of maternal hypertension and pre-eclampsia, spontaneous abortion, Caesarean delivery, low birthweight, birth prematurity, perinatal mortality, admission to neonatal intensive care and extended length of care, respiratory distress, cerebral palsy, developmental delay, contact with disability services and mortality to age 5 years. Premature birth, which affects 97% of triplets and 53.3% of twins in Australia, is not the sole factor involved. The rate of multiple pregnancy in Australia is 1.7%. This compares to 22.1% for pregnancies resulting from assisted reproduction technology (ART). As a result, 21.8% of babies born from ART are from a multiple pregnancy, in comparison to the USA where the majority of babies born from ART are from a multiple pregnancy. Additionally, the population rate of multiple births is rising due to the more frequent use of ART and continued multi-embryo transfers, which is operating against a background of rising implantation rates within ART clinics. Twins have been of interest from a programming perspective. However, analysis of associations between crude birthweight and subsequent metabolic risk factors or mortality in adulthood from chronic disease indicate that adaptations in pregnancy to support multi-fetal growth are not identical to fetal growth restriction in singleton pregnancies. Indeed, the process of ‘maternal constraint’ is incompletely understood and confounds such comparisons. From a programming perspective, it is a challenge to identify in twin pregnancies the transition from physiological adaptation to pathological growth restriction. Growth disparity between twins has been more illuminating of subtle adverse effects for the smaller of twin pairs in both blood pressure and insulin resistance in adulthood. Interestingly, these effects can be observed in both dizygotic and to a lesser degree in monozygotic twins, which indicates a role for both genetic and environmental factors in these measures. This suggests that, consistent with experimental studies in other species, the relationship between impaired growth in utero and chronic disease in later life is not simply mediated by a common genetic pathway.

Perinatal outcome of ICSI pregnancies compared with a matched group of natural conception pregnancies in Flanders (Belgium): a cohort study

A retrospective cohort study was conducted with an intracytoplasmic sperm injection (ICSI) group and a naturally conceived comparison group. A total of 1655 singleton and 1102 twin ICSI births were studied with regard to perinatal outcome. Control subjects (naturally conceived pregnancies) were selected from a regional registry and were matched for maternal age, parity, place of delivery, year of birth and fetal sex. The main outcome measures were duration of pregnancy, birth weight, Apgar score <5 after 5 min, neonatal complications, perinatal death and congenital malformations. Twin births, when compared with singletons, carry a much higher risk of poor perinatal outcome. For both ICSI singletons and ICSI twins, no significant difference was found between ICSI and naturally conceived pregnancies for all investigated parameters. After excluding like-sex twin pairs, ICSI twin pregnancies were at increased risk for perinatal mortality (OR = 2.74, CI = 1.26-5.98), prematurity (OR = 1.38, CI = 1.10-1.75) and low birth weight (OR = 1.34, CI = 1.06-1.69) compared with spontaneously conceived different-sex twin pairs. In conclusion, the perinatal outcome of ICSI singleton and twin pregnancies was very similar to that of spontaneously conceived pregnancies in this large cohort study. After excluding like-sex twin pairs, ICSI twins were at increased risk for prematurity, low birth weight and higher perinatal mortality compared with the natural conception comparison group.

Perinatal outcome of twin pregnancies after in vitro fertilization

BACKGROUND

There are conflicting data concerning perinatal outcome of twin, in vitro fertilization (IVF) pregnancies. The aim of this study was to evaluate and compare perinatal and neonatal outcomes in twin IVF pregnancies to those of spontaneously conceived twin gestations.

METHODS

The medical files of 73 IVF and 148 naturally conceived twin pregnancies were studied retrospectively. Data concerning maternal characteristics, obstetric complications, and neonatal outcome were recorded and compared by chi2 test. The one-way analysis of variance (anova) was used to compare the means of groups.

RESULTS

Mean maternal age, the proportion of nulliparous women, and the incidence of premature rupture of membranes, cesarean section, and premature delivery were significantly higher in the study group. The mean birthweight was significantly lower, the frequency of admission to the intensive care unit and the duration of hospitalization were significantly higher in the study group. The incidence of intraventricular hemorrhage was significantly higher in the IVF group. The number of perinatal deaths was similar.

CONCLUSION

IVF twin pregnancies are at greater risk for obstetric complications and adverse neonatal outcome in comparison with naturally conceived twin gestations.

Risk factors for adverse outcomes in spontaneous versus assisted conception twin pregnancies

OBJECTIVE

To evaluate risk factors for adverse outcomes in spontaneous vs. assisted conception twin pregnancies.

DESIGN

Historical cohort study.

SETTING

Four academic tertiary medical centers.

PATIENT(S)

Women with twin pregnancies, including 2,143 spontaneous and 424 assisted conception; 2,492 nonreduced and 75 reduced.

INTERVENTION(S)

None (observational).

MAIN OUTCOME MEASURE(S)

Preeclampsia, preterm premature rupture of membranes, birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth (<10th percentile between 20 and 28 weeks).

RESULT(S)

Among nonreduced pregnancies, assisted conception was not significantly associated with any adverse outcomes; among nulliparas, the risk for preeclampsia was increased regardless of method of conception; among spontaneous conceptions, the risks for preterm premature rupture of membranes, low birth weight, very low birth weight, and slowed midgestation fetal growth were increased. Among all pregnancies, fetal reduction increased risks for birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth. Among nulliparas with assisted conceptions, fetal reduction increased the risks for birth <30 weeks, very low birth weight, and slowed midgestation fetal growth.

CONCLUSION(S)

These findings indicate that in twin pregnancies, assisted conception is not a risk factor for adverse outcomes, but rather specific factors that are more common among these pregnancies, such as nulliparity and fetal reduction, increase risks.

Perinatal outcome of singletons and twins after assisted conception: a systematic review of controlled studies

OBJECTIVE

To compare the perinatal outcome of singleton and twin pregnancies between natural and assisted conceptions.

DESIGN

Systematic review of controlled studies published 1985-2002.

STUDIES REVIEWED

25 studies were included of which 17 had matched and 8 had non-matched controls.

MAIN OUTCOME MEASURES

Very preterm birth, preterm birth, very low birth weight, low birth weight, small for gestational age, caesarean section, admission to neonatal intensive care unit, and perinatal mortality.

RESULTS

For singletons, studies with matched controls indicated a relative risk of 3.27 (95% confidence interval 2.03 to 5.28) for very preterm (< 32 weeks) and 2.04 (1.80 to 2.32) for preterm (< 37 weeks) birth in pregnancies after assisted conception. Relative risks were 3.00 (2.07 to 4.36) for very low birth weight (< 1500 g), 1.70 (1.50 to 1.92) for low birth weight (< 2500 g), 1.40 (1.15 to 1.71) for small for gestational age, 1.54 (1.44 to 1.66) for caesarean section, 1.27 (1.16 to 1.40) for admission to a neonatal intensive care unit, and 1.68 (1.11 to 2.55) for perinatal mortality. Results of the non-matched studies were similar. In matched studies of twin gestations, relative risks were 0.95 (0.78 to 1.15) for very preterm birth, 1.07 (1.02 to 1.13) for preterm birth, 0.89 (0.74 to 1.07) for very low birth weight, 1.03 (0.99 to 1.08) for low birth weight, 1.27 (0.97 to 1.65) for small for gestational age, 1.21 (1.11 to 1.32) for caesarean section, 1.05 (1.01 to 1.09) for admission to a neonatal intensive care unit, and 0.58 (0.44 to 0.77) for perinatal mortality. The non-matched studies mostly showed similar trends.

CONCLUSIONS

Singleton pregnancies from assisted reproduction have a significantly worse perinatal outcome than non-assisted singleton pregnancies, but this is less so for twin pregnancies. In twin pregnancies, perinatal mortality is about 40% lower after assisted compared with natural conception.

Maternal risks and perinatal outcome in a Danish national cohort of 1005 twin pregnancies: the role of in vitro fertilization

BACKGROUND

Twin pregnancies constitute 25% of all in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) pregnancies. There is a lack of knowledge on maternal risks and perinatal outcome of IVF/ICSI twin pregnancies.

METHODS

National survey by questionnaire (n = 1769). The study population consisted of all IVF/ICSI twin mothers (n = 266) and the two control groups of all IVF/ICSI singleton mothers (n = 764) and non-IVF/ICSI twin mothers (n = 739) who delivered in Denmark in 1997. The response rate was 89% among IVF twin mothers and overall 81%.

RESULTS

In terms of maternal risks and perinatal outcome no significant differences were observed between IVF/ICSI twin and non-IVF/ICSI twin pregnancies after stratification for maternal age and parity. Nevertheless, IVF/ICSI twin mothers were more frequently on sick leave (OR 2.5, 95% CI 1.5-4.0) and hospitalized (OR 1.9, 95% CI 1.3-2.8) during pregnancy. Compared with IVF/ICSI singleton pregnancies, IVF/ICSI twin pregnancies were characterized by a higher incidence of preeclampsia (OR 2.4, 95% CI 1.5-4.2) and a higher frequency of sick leave (OR 6.8, 95% CI 4.4-10.5) and hospitalizations during pregnancy (OR 3.5, (95% CI 2.5-4.9); moreover, mean birthweight (p < 0.001) and gestational age (p < 0.001) were lower. No differences were observed in the incidence of pregnancy-induced hypertension and gestational diabetes between IVF/ICSI twin and singleton pregnancies.

CONCLUSION

Although this population study indicates that maternal risks in IVF/ICSI twin pregnancies are comparable with non-IVF/ICSI twin pregnancies, the IVF/ICSI twin mothers were more likely to be on sick leave or hospitalized during pregnancy. Furthermore, maternal risks were higher and obstetric outcome poorer in IVF/ICSI twin vs. IVF/ICSI singleton pregnancies.

Pregnancy complications, obstetric risks, and neonatal outcome in singleton and twin pregnancies after GIFT and IVF

PURPOSE

In vitro fertilization (IVF) and to a lower extent gamete intra-fallopian transfer (GIFT) have become routine infertility treatments in industrialized countries. Our purpose is to compare the obstetric and neonatal characteristics of singleton and twin pregnancies after GIFT and IVF with those conceived spontaneously.

METHODS

This case-control study was conducted in a tertiary care medical center. The 322 singleton and 78 twin pregnancies after GIFT or IVF from 1991 through 1996 were evaluated and compared with each other, and with a control group that conceived spontaneously and matched for parity, maternal and gestational age. Statistical significance of differences was assessed by chi(2) test or two-tailed Fisher exact test. Continuous variables were compared by the paired t-test.

RESULTS

Pregnancy-induced hypertension (PIH) and vaginal bleeding were significantly more frequent maternal complications in the GIFT/IVF singleton groups compared to controls. In twin pregnancies the rate of cesarean sections, vaginal bleeding and preterm labor were more common after GIFT/IVF but did not reach statistical significance. Assisted reproduction was associated with low birth weight only in twin pregnancies when controlled for confounding variables, however perinatal outcome was comparable. There was no significant difference in the outcome measures between GIFT and IVF pregnancies.

CONCLUSION

After controlling for parity, maternal and gestational age, singleton pregnancies conceived by GIFT/IVF are at increased obstetrical risk, however the perinatal outcome is comparable despite a lower average birth weight.