Urinary oestriol excretion in twin pregnancies

Pre- and perinatal factors and incidence of breast cancer in the Black Women's Health Study

PURPOSE

The purpose of the study was to investigate the association between pre- or perinatal factors and breast cancer risk among African American women.

METHODS

Participants in the Black Women's Health Study, a prospective cohort of 59,000 African American women, reported birth weight, preterm birth, twin or triplet status, maternal age at birth, birth order, and having been breastfed during infancy at various times during follow-up from 1997 to 2015. Numbers of incident cases ranged from 312 for breastfed analyses to 1,583 for twin or triplet analyses. Using multivariable Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between each factor and breast cancer risk overall and by estrogen receptor (ER) status.

RESULTS

Compared to birth weights of 5 lbs. 8 oz.-8 lbs. 13 oz., low (< 5 lbs. 8 oz.) and high (> 8 lbs. 13 oz.) birth weights were associated with increased breast cancer risk; HRs (95% CI) were 1.19 (0.98-1.44) and 1.26 (0.97-1.63), respectively. Associations were similar by ER status. Having been born to a mother aged ≥ 35 years versus < 20 years was associated with risk of ER+ (HR 1.59, 95% CI 1.10-2.29), but not ER- breast cancer. Other perinatal factors were not associated with breast cancer.

CONCLUSION

African American women with a low or high birth weight or born to older mothers may have increased breast cancer risk. Trends towards delayed child birth and higher birth weights, coupled with disproportionately high rates of low birth weight among African Americans, may contribute to increases in breast cancer incidence.

Circulating maternal and umbilical cord steroid hormone and insulin-like growth factor concentrations in twin and singleton pregnancies

In addition to being associated with a higher risk of complications during pregnancy, twinning may also be a proxy for altered hormonal exposure for mothers and twin offspring, with implications for their health later in life. We compared maternal and fetal steroid hormone and insulin-like growth factor concentrations between singleton (n=62) and twin (n=41) pregnancies. Maternal concentrations of androgens, estrogens, insulin-like growth factor (IGF)-1, IGF-binding protein (BP)-3 and prolactin were quantified during the third trimester and at delivery, as well as in the fetal circulation at birth. Geometric means accounting for gestational age were calculated for hormone concentrations and compared between matched twin and singleton pregnancies. Most maternal hormone concentrations were modestly higher in twin than in singleton pregnancies in the third trimester (ranging from 8.3% for IGF-1 to 17.1% for estradiol) and at delivery (ranging from 11.1% for IGFBP-3 to 15.2% for estriol). Cord serum hormones were generally similar in twin and singleton pregnancies, except for IGFBP-3, which was 200% lower in twins. The modest differences in maternal hormones in late gestation seem unlikely to explain alterations in hormonally related disease risk in mothers of twins compared with singletons. The large deficit of IGFBP-3 in the fetal circulation of twins at birth may allow for sufficient concentrations of IGF-2 for growth and development in an environment of shared nutritional resources.

Not only pregnancy but also the number of fetuses in the uterus affects intraocular pressure

Aim:

To investigate whether, intraocular pressure (IOP) is affected when there is a second fetus in the uterus during pregnancy.

Materials and Methods:

Eighty eyes of 40 twin pregnancies (TwPs), 80 eyes of 40 singleton pregnancies (SiPs) and 80 eyes of 40 non-pregnant females (NoPs) were included in the study.

Statistical Analysis:

Repeated measurements analysis of variance with two factors, one-way analysis of variance (ANOVA) and theTukey's multiple comparison test were used.

Results:

The mean IOP (MIOP) values in TwPs were 14.29 ± 1.28, 11.48 ± 1.20, and 9.81 ± 1.36 mmHg and the MIOP values in SiPs were 14.42 ± 0.95, 13.12 ± 0.75, and 10.97 ± 0.89 mmHg in subsequent trimesters. The MIOP values in NoPs were 14.77 ± 1.18, 14.92 ± 1.33, and 15.08 ± 0.89 mmHg in subsequent 3-month measurements. The results show that the MIOP values for the TwPs group were significantly lower than the SiPs in all trimesters.

Conclusions:

During pregnancy, the number of fetuses in the uterus is an indirectly important factor that influences the decrease in IOP. We hypothesize that the increased ocular hypotensive effect of TwPs is most likely related to the presence of higher levels of hormones, particularly estrogen, progesterone and relaxin compared with SiPs.

Intrauterine environments and breast cancer risk: meta-analysis and systematic review

Introduction

Various perinatal factors, including birth weight, birth order, maternal age, gestational age, twin status, and parental smoking, have been postulated to affect breast cancer risk in daughters by altering the hormonal environment of the developing fetal mammary glands. Despite ample biologic plausibility, epidemiologic studies to date have yielded conflicting results. We investigated the associations between perinatal factors and subsequent breast cancer risk through meta-analyses.

Methods

We reviewed breast cancer studies published from January 1966 to February 2007 that included data on birth weight, birth order, maternal age, gestational age, twin status, and maternal or paternal smoking. Meta-analyses using random effect models were employed to summarize the results.

Results

We found that heavier birth weights were associated with increased breast cancer risk, with studies involving five categories of birth weight identifying odds ratios (ORs) of 1.24 (95% confidence interval [CI] 1.04 to 1.48) for 4,000 g or more and 1.15 (95% CI 1.04 to 1.26) for 3,500 g to 3,999 g, relative to a birth weight of 2,500 to 2,599 g. These studies provided no support for a J-shaped relationship of birthweight to risk. Support for an association with birthweight was also derived from studies based on three birth weight categories (OR 1.15 [95% CI 1.01 to 1.31] for ≥4,000 g relative to <3,000 g) and two birth weight categories (OR 1.09 [95% CI 1.02 to 1.18] for ≥3,000 g relative to <3,000 g). Women born to older mothers and twins were also at some increased risk, but the results were heterogeneous across studies and publication years. Birth order, prematurity, and maternal smoking were unrelated to breast cancer risk.

Conclusion

Our findings provide some support for the hypothesis that in utero exposures reflective of higher endogenous hormone levels could affect risk for development of breast cancer in adulthood.

Ritodrine pharmacokinetics in twin pregnancy patients

OBJECTIVES

To establish a rational ritodrine therapy in relation to serum ritodrine concentration, we examined 14 twin pregnancy patients and determined their pharmacokinetic data.

METHODS

We measured serum concentrations of ritodrine in twin pregnancy patients using high-performance liquid chromatography (HPLC).

RESULTS

The twin pregnancy patients all exhibited linear ritodrine pharmacokinetic profiles. There was a statistically significant but slight negative correlation between gestation period and ritodrine clearance (y=-0.038x+2.75, r=0.349, p<0.001) among all patients. However, when analyzed on an individual basis, there was a high correlation found in three of the 14 patients.

CONCLUSION

Due to a decrease in total body clearance in three of the 14 patients, overall serum concentration of ritodrine increased at the end of the pregnancies. To further characterize ritodrine kinetics, additional studies are needed to determine an effective and safe therapy for ritodrine use in twin pregnancy patients.

Prenatal Diethylstilbestrol Exposure and Risk of Breast Cancer

It has been hypothesized that breast cancer risk is influenced by prenatal hormone levels. Diethylstilbestrol (DES), a synthetic estrogen, was widely used by pregnant women in the 1950s and 1960s. Women who took the drug have an increased risk of breast cancer, but whether risk is also increased in the daughters who were exposed in utero is less clear. We assessed the relation of prenatal DES exposure to risk of breast cancer in a cohort of DES-exposed and unexposed women followed since the 1970s by mailed questionnaires. Eighty percent of both exposed and unexposed women completed the most recent questionnaire. Self-reports of breast cancer were confirmed by pathology reports. Cox proportional hazards regression was used to compute incidence rate ratios (IRR) for prenatal DES exposure relative to no exposure. During follow-up, 102 incident cases of invasive breast cancer occurred, with 76 among DES-exposed women (98,591 person-years) and 26 among unexposed women (35,046 person-years). The overall age-adjusted IRR was 1.40 [95% confidence interval (95% CI), 0.89-2.22]. For breast cancer occurring at ages >or=40 years, the IRR was 1.91 (95% CI, 1.09-3.33) and for cancers occurring at ages >or=50 years, it was 3.00 (95% CI, 1.01-8.98). Control for calendar year, parity, age at first birth, and other factors did not alter the results. These results, from the first prospective study on the subject, suggest that women with prenatal exposure to DES have an increased risk of breast cancer after age 40 years. The findings support the hypothesis that prenatal hormone levels influence breast cancer risk.

Gender mix in twins and fetal growth, length of gestation and adult cancer risk

This study evaluated the effect of gender mix (the gender combinations of twin pairs) on fetal growth and length of gestation, and reviewed the literature on the long-term effects of this altered fetal milieu on cancer risk. In singletons, it is well established that females weigh less than males at all gestations, averaging 125-135 g less at full term. This gender difference is generally believed to be the result of the effect of androgens on fetal growth. The gender difference in fetal growth is greater before the third trimester and less towards term, with males growing not only more, but also earlier than females. Plurality is a known risk factor for reduced fetal growth and birthweight. Compared with singletons, the mean birthweight percentiles of twins fall substantially (by 10% or more) below the singleton 10th percentile by 28 weeks, below the singleton 50th percentile by 30 weeks, and below the singleton 90th percentile by 34 weeks. In unlike-gender twin pairs, it has been reported that the female prolongs gestation for her brother, resulting in a higher birthweight for the male twin than that of like-gender male twins. Other researchers have demonstrated that females in unlike-gender pairs had higher birthweights than females in like-gender pairs. Analyses from our consortium on 2491 twin pregnancies with known chorionicity showed longer gestations and faster rates of fetal growth in both males and females in unlike-gender pairs compared with like-gender male or female pairs, although these differences were not statistically significant. The post-natal effects for females growing in an androgenic-anabolic environment include increased sensation-seeking behaviour and aggression, lowered visual acuity, more masculine attitudes and masculinising effects of the auditory system and craniofacial growth. In contrast, there is no evidence to suggest that there might be a similar feminising effect on males from unlike-gender pairs. This hormonal exposure in utero may influence adult body size and susceptability to breast cancer.

Do estrogens always increase breast cancer risk?

The etiology of breast cancer is closely linked to the female hormone estrogen, with high life-time exposure being suggested to increase breast cancer risk [Nature 303 (1983) 767]. However, there appears to be a disparity between studies attempting to establish an association between high estrogen levels and breast cancer risk. This disparity becomes smaller by taking into consideration a timing factor, and we propose that estrogens can increase, decrease, or have no effect on breast cancer risk, depending on the timing of estrogen exposure. We further propose that the timing of estrogenic exposures may play at least as important a role in affecting breast cancer risk as life-time exposure.

Twinship and risk of postmenopausal breast cancer

BACKGROUND

Intrauterine exposure to high levels of endogenous estrogens has been hypothesized to increase the risk of breast cancer. Because estrogens and other pregnancy hormones are substantially elevated in twin pregnancies, and possibly more so in dizygotic twin pregnancies, we evaluated the association between aspects of twin membership (i.e., belonging to a twin pair) and the risk of breast cancer.

METHODS

In a cohort of 29 197 postmenopausal Iowa women with no prior diagnosis of cancer (except for nonmelanoma skin cancer), breast cancer risk factors were determined by use of a mailed questionnaire in 1986 (baseline); twin membership, sex of the twin, and zygosity were determined by use of a follow-up questionnaire in 1992.

RESULTS

Within the cohort, 1.8% (n = 538) of the women reported being a twin; of these, 24% (n = 130) were monozygotic twins, 63% (n = 337) were dizygotic twins, and 13% (n = 71) did not know their zygosity. From 1986 through 1996, 1230 breast cancers in the cohort were ascertained by linkage to the Iowa Cancer Registry. Compared with singletons, women who belonged to a twin pair were at elevated risk of breast cancer (multivariate-adjusted risk ratio [RR] = 1.72; 95% confidence interval [CI] = 1.22-2.42), with adjustment for educational level, family history of breast cancer, height, body mass index, body fat distribution, age at menarche, age at first live birth, use of hormone replacement therapy, and alcohol use. Multivariate-adjusted risk was elevated (in comparison with singletons) if the sex of the other twin was female (RR = 1.82; 95% CI = 1.20-2.75); however, this risk was limited to female dizygotic twins (RR = 2.14; 95% CI = 1. 21-3.79), since no excess risk was evident for monozygotic twins (RR = 1.04; 95% CI = 0.43-2.50). The risk to women with a male twin was also elevated (RR = 1.49; 95% CI = 0.80-2.78) in comparison with singletons, but this estimate was not statistically significant.

CONCLUSIONS

This cohort study lends further support to the theory that there are important intrauterine influences on carcinogenesis of the breast.

Maternal nutrition in twin gestations: weight gain, cravings and aversions, and sources of nutrition advice

BACKGROUND

Maternal nutrition has a strong influence on singleton and twin birthweight. This study evaluated the association between twin birthweight and maternal pregravid body mass index (BMI), weight gain, and cravings and aversions. Information was also obtained regarding sources of nutrition advice and advised versus actual weight gain.

METHODS

This study is based on data from interviews with 928 mothers of twins. Univariate analysis included comparisons by source of nutritional advice, birthweight categories, and categories of cravings and aversions. Multiple logistic regression was used to formulate models for mean twin birthweights > 1,500 g and > 2,500 g.

RESULTS

Mothers who received their nutrition advice from a registered dietitian had the highest weight gains and the lowest proportion of birthweights < 1,500 g. For mean twin birthweight > 2,500 g, the final model included prematurity, pregravid BMI, and weight gain; for birthweights > 1,500 g, the model additionally included maternal age and aversions.

CONCLUSIONS

Maternal pregravid BMI and gestational weight gain were shown to be important factors influencing twin birthweight. Nutrition advice, particularly from a registered dietitian, may be vital in assuring adequate weight gain, and therefore better birthweights, for these high-risk pregnancies.

Intrauterine environment and breast cancer risk in women: a population-based study

BACKGROUND

The established risk factors for female breast cancer, including nulliparity, age at first birth, age at menarche, and age at menopause, do not adequately explain the occurrence pattern of this cancer. Therefore, additional factors need to be considered to advance our understanding of the causes of breast cancer. Evidence obtained from animals and humans indicates that the perinatal period may be particularly important. Our earlier studies, based on a subsample of the present investigation, suggested that factors thought to be positively associated with estrogen levels during pregnancy are positively associated with breast cancer risk. However, the associated confidence intervals (CIs) were generally wide, indicating considerable variability in the data.

PURPOSE

We studied a large number of incident breast cancer case patients and evaluated several perinatal variables in relation to breast cancer risk. These variables included some not previously studied, such as gestational age and neonatal jaundice. We also investigated twin membership as a predictor variable and death from breast cancer, in addition to occurrence of breast cancer, as an alternative outcome variable.

METHODS

Birth records for all deliveries at five different hospitals in Sweden during the period from 1874 through 1961 were used to define a large cohort of women. Incident case patients with breast cancer in this cohort were ascertained through the National Cancer Registry or the Uppsala Regional Cancer Registry from 1958 through 1994. In a case-control study nested in the cohort, we abstracted data from birth records on 1068 women with incident breast cancer and on 2727 control subjects individually matched to the case patients on date of birth. We modeled the data through conditional logistic regression. All P values were derived from two-sided statistical tests.

RESULTS

We found a markedly reduced risk for breast cancer in women whose mothers had pregnancy toxemia (odds ratio [OR] = 0.41; 95% CI = 0.22-0.79) and an excess risk on women who had neonatal jaundice (OR = 2.16; 95% CI = 1.27-3.67) or who were born before 33 weeks of gestation (OR = 3.96; 95% CI = 1.45-10.81). Compared with the risk for breast cancer in the singleton, the risk for breast cancer in dizygotic twins was increased, although this increase was not statistically significant (OR = 1.72; 95% CI = 0.92-3.20). There was no evidence in these data for a statistically significant or substantial association of breast cancer risk with birth size indicators (i.e., weight and length at birth and placental weight).

CONCLUSION AND IMPLICATIONS

Because pregnancy toxemia is associated with low levels of estrogens and neonatal jaundice, severe prematurity, and dizygotic twins with high levels of estrogens, our findings suggest that estrogens and other hormonal factors, known to influence breast cancer risk in the adult, may also play a critical role during the intrauterine period.

Effect of twinship on incidence of cancer of the testis, breast, and other sites (Sweden)

It has been suggested that cancers of the testis and breast are associated with exposure to estrogens and other hormones in utero. Twin pregnancies have higher levels of pregnancy-associated hormones than singleton pregnancies, and these levels may be higher in dizygotic than in monozygotic twin pregnancies. Through a large population-based study of twins, we assessed the hypothesis that levels of pregnancy-associated hormones have etiologic importance for cancers of the testis, breast, and other sites. The incidence of all cancers among 46,767 members of the Swedish Twin Registry was compared with the incidence among the Swedish general population. We found testicular cancer excess among dizygotic twins (observed/expected[O/E ratio = 2.3, CI = 1.1-4.2) compared with older men (O/E ratio = 1.2, CI = 0.5-2.4). In addition, a substantially elevated incidence of breast cancer was observed in dizygotic twin women aged 20 to 29 years (O/E = 6.7, CI = 2.9-13.1). None of the other age or zygosity groups showed notable elevations in incidence of testicular, breast, or other cancers. We conclude that dizygotic twinship may be associated with cancer of the breast and testis among young adults. These findings support the concept that pregnancy hormones are associated with risk of testicular and breast cancer, although non-hormonal aspects of twin pregnancy that vary with respect to zygosity cannot be excluded as explanatory factors.

Prevalence of a history of testicular cancer in a cohort of elderly twins

Prior studies have suggested that the risk of testicular cancer among dizygotic twins may exceed that among monozygotic twins or the general population. Cryptorchidism is associated with testicular cancer and twinship, and therefore might potentially explain the findings of the prior studies. In 1993-1994, when they were 66 to 77 years of age, 14,326 twin individuals in the National Academy of Sciences-National Research Council Twin Registry were interviewed by telephone. A history of testicular cancer was reported by 5 (0.08%) of 5951 monozygotic twins and 11 (0.16%) of 6992 dizygotic twins. Follow-up interviews concerning testicular cancer risk factors and treatment were able to be administered to 4 of the monozygotic and 9 of the dizygotic twins reporting testicular cancer. A history of cryptorchidism was reported in the follow-up interview by only one dizygotic twin. Our data agree with the results of prior studies reporting a more frequent occurrence of testicular cancer among dizygotic than monozygotic twins. Although somewhat limited by small numbers, our study also suggests that the findings of increased testicular cancer in dizygotic twins are not explained simply by increased occurrence of cryptorchidism in twins.

Human placental lactogen and unconjugated estriol concentrations in twin pregnancy: monitoring of fetal development in intrauterine growth retardation and single intrauterine fetal death

Human placental lactogen and unconjugated estriol concentrations in maternal serum were evaluated in 100 uneventful twin pregnancies, and these values were compared with those observed in 16 twin pregnancies associated with intrauterine growth retardation or single intrauterine fetal death. In pregnancies associated with intrauterine growth retardation (n = 8), human placental lactogen levels were at the lower limit of normal range for singleton pregnancies, whereas estriol levels were normal in most cases. When one of the fetuses had died before week 33 of pregnancy (n = 5), both human placental lactogen and estriol levels were low and they were almost at the levels in singleton pregnancy. When intrauterine fetal death occurred after week 36 of pregnancy (n = 3), both hormone levels remained normal until term. Thus human placental lactogen rather than estriol is a good indicator of intrauterine growth retardation in twin pregnancy. Both human placental lactogen and estriol are useful for the monitoring of the surviving fetus in the case of single intrauterine fetal death.

Human placental lactogen and dU-estrogen levels in normal twin pregnancies

Reference intervals for human placental lactogen (hPL) and dU-estrogens (dU-E) in uncomplicated twin pregnancies are found to be higher than singleton pregnancies and considerably wider. Significantly more monozygotic than dizygotic pregnancies, and significantly more monoplacental than diplacental pregnancies showed hPL values below the median on the normal range curve. The same was not found for dU-E. Significantly more growth-retarded fetuses were found in monoplacental than diplacental pregnancies. The benefit of measuring the two parameters in order to identify the intrauterine growth retarded fetuses were evaluated in terms of sensitivity and specificity. Both parameters were found less suitable for the purpose.

The relationship between gestational age and birth-weight in twin pregnancy

Analysis is made of fetal growth in 563 twin pregnancies. The birth-weight of a twin is affected by the duration of pregnancy and zygosity. Intrauterine growth and weight is the same as a singleton pregnancy up to a gestational age of 32 weeks. After this stage fetal growth slows markedly. The growth curves of both twins are similar with an increasing tendency towards growth retardation in twin 2 after 39 weeks' gestation. Intrauterine growth retardation, as represented by the 10th percentile line, for twin 1 joins 1,094g at 31 weeks, 1,836g at 36 weeks and 2,428g at 40 weeks' gestation. The corresponding figures for twin 2 are 1,131g, 1,875g and 2,337g respectively.

Detection of the small-for-gestational age twin fetus by a two-stage ultrasound examination schedule

Serial ultrasonic measurement of the biparietal diameter is an unsatisfactory means of detecting the small-for-gestational age (SGA) fetus in twin pregnancies. A new two-stage ultrasound examination schedule, highly effective in detecting the SGA singleton fetus, has been evaluated prospectively in 31 twin pregnancies. The schedule comprises ultrasonic assessment of gestational age in early pregnancy, followed by measurement of the product of the crown-rump length and trunk area of both fetuses at 34-36 weeks. All Nineteen SGA twin fetuses were detected using this schedule; the technique offers several other advantages over serial biparietal cephalometry.

The prediction of fetal growth retardation in twin pregnancy

A total of 132 twin pregnancies first seen at less than 36 weeks gestation were studied prospectively to determine the epidemiological and anthropomorphic factors associated with single or dual fetal growth retardation; the clinical, biochemical and ultrasound serial measurements that are predictive of single or dual fetal growth retardation, and to design scoring systems for the prediction of fetal growth retardation. A number of factors were associated with an increased risk of fetal growth retardation, but the highest risk was present when there was an abnormality in both plasma oestriol and placental lactogen, and the biparietal diameter growth rates were divergent. Scoring systems were derived using multi-variant discriminant analysis for three clinical situations: the patient seen for the first or second time; where only clinical facilities exist and the patient was seen on three or more occasions; and where facilities exist for the biochemical tests of placental function and ultrasonic measurement of the biparietal diameters. The scoring system for the last situation had the highest predictive rate and the lowest false positive rate.

The merits of special antenatal care for twin pregnancies

A combined series of 101 twin pregnancies for whom routine hospital rest during the last trimester was replaced by intensified antenatal care in a special twins clinic was studied. Perinatal mortality and morbidity was similar to that found in a comparison group of 137 twin pregnancies under the care of consultants and not referred to the twins clinic. Routine cervical assessments and uterine activity measurements were unhelpful in predicting premature delivery. Urinary oestrogens and ultrasonic measurements of fetal biparietal diameter were of little or no value in predicting weight for gestational age but the ultrasonic measurement of abdominal circumference provided limited information on fetal growth. The contribution of a placebo effect to the results of patients receiving more personalised care cannot be discounted.

Detection of the small-for-dates twin fetus by ultrasound

As methods for identifying the small-for-dates fetus in twin pregnancies, serial ultrasonic cephalometry and a new two-stage ultrasound examination schedule have been evaluated and compared. Serial cephalometry is associated with technical and interpretative problems, and only 24 (56 per cent) of 43 small-for-dates fetuses in 66 retrospectively studied twin pregnancies showed detectably abnormal biparietal diameter growth. The two-stage schedule comprises an accurate assessment of gestational age in early pregnancy, and determination of the product of the crown-rump length and trunk area at 34 to 36 weeks; this identified all 15 small-for-dates fetuses in 21 prospectively studied twin pregnancies, and the method offers several other advantages over serial cephalometry.

Antepartum fetal heart rate monitoring in multiple pregnancy

The assessment of fetal wellbeing in patients with multiple pregnancy by nonstressed antepartum cardiotocography is technically feasible and of clinical value. In 50 patients (101 babies) who were monitored during the antepartum period, there were five patients in whom one of a pair of twins showed a non-reactive cardiotogram. Four of these babies died (two intrauterine deaths and two neonatal deaths). All of these five babies were growth retarded at birth. The cardiotocograms from the other 96 fetuses were 'reactive' and these babies were normal. Cardiotocography seems to be a better predictor of perinatal mortality and morbidity than serial urinary oestrogens or serial biparietal diameter measurements in multiple pregnancy.

Diagnosis and treatment of twin pregnancy

Early detection is a prerequisite for the active management of twin pregnancy. Detection rate was not, or was only slightly, increased by improved anamnesis or more alert physical examination. General placental lactogen screening selected 95% of the twins but implied a subsequent ultrasonic screening examination of 16% of the pregnant population for the definitive diagnosis. A general screening programme with ultrasound detected 90% of the twin pregnancies (methodological error 1.7%; not participating 8%) in the mid-trimester. Extensive restriction of maternal physical activity from the 29th to the 36th gestational week by bed rest in hospital reduced perinatal mortality to the level of singletons and also decreased the incidence of neurological and mental handicap among the surviving twins. For the supervision of twin pregnancy, urinary estriol estimates predict birth weight rather than fetal distress. Monitoring with repeated ultrasonic biparietal diameter measurements seem limited in value; even large intertwin BPD differences are not indicators of fetal distress in the smallest twin. The decrease of perinatal mortality and morbidity among twins subjected to special antenatal supervision suggests that large gains can be made by early detection and antenatal hospitalization. The earlier finding that impairment of the intrauterine supply line is closely associated with neurological sequelae gives added importance to the reduction of CNS handicap and of growth-retarded fetuses observed during such a programme.

Human placental lactogen, estradiol-17beta, and progesterone levels in the third trimester and their respective values for detecting twin pregnancy

Plasma levels of HPL, P, and E2 was serially measured between weeks 30 to 36 in simplex and duplex pregnancies. Levels of both HPL and P were significantly higher in duplex than in simplex pregnancies. However, this was not the case for E2. There was a significant correlation between HPL and P levels. It is indicated that measurement of plasma P levels, as those of HPL levels, but not E2 levels is of value for detecting twin pregnancy.

Triplet pregnancy and Rhesus isoimmunization

A case of Rh isoimmunization complicating triplet pregnancy is reported and the rarity of the combination is noted. The management of Rh immunized pregnancy is review with particular reference to problems associated with plural pregnancy. The findings confirm earlier reports that fetal or placental influences as well as antibody titres determine the severity of erythroblastosis.

Circulating maternal serum progesterone in high-risk pregnancies

Serum progesterone was measured by competitive protein-binding assay in 331 cases of normal pregnancy ranging from 6 to 42 weeks. Serial estimations of serum progesterone were performed in nine cases of severe hypertensive disorder of pregnancy, eight cases of twin pregnancy, three cases of twin pregnancy complicated by severe hypertensive disorder of pregnancy, three cases of triplet pregnancy, three cases of previous bad obstetric history, one case of anencephaly, and seven cases of intrauterine fetal death. Serum progesterone remained within normal range in severe hypertensive disorder of pregnancy and the levels were indistinguishable in cases of fetal growth retardation from those without growth retardation. In twin and triplet pregnancies, serum progesterone was within normal range or elevated and was usually higher than normal in twin pregnancies after weeks 33 to 34. Serum progesterone levels were normal in anencephalic pregnancy and in most cases of intrauterine fetal death. The findings are discussed with reference to placental hormonal activity. It is concluded that serum progesterone is a poor index of placental function.