Association of extreme first-trimester free human chorionic gonadotropin-beta, pregnancy-associated plasma protein A, and nuchal translucency with intrauterine growth restriction and other adverse pregnancy outcomes

OBJECTIVE: The purpose of this study was to determine the association between first-trimester trisomy 21 screening markers (free human chorionic gonadotropin-beta [hCG], pregnancy-associated plasma protein A [PAPP-A], and nuchal translucency) and adverse pregnancy outcome. STUDY DESIGN: This was a cohort study of 8012 patients enrolled in a National Institute of Child Health and Human Development-sponsored study of first-trimester trisomy 21 and 18 screening. Trisomy 21 and 18 risk results and individual marker levels in unaffected pregnancies and pregnancies with adverse outcomes were evaluated. RESULTS: PAPP-A <1st percentile (OR 5.4, 95% CI 2.8-10.3) and PAPP-A <5th percentile (OR 2.7, 95% CI 1.9-3.9) and free beta-hCG <1st percentile (OR 2.7, 95% CI 1.3-5.9) were associated with increased risk of intrauterine growth restriction (IUGR) with positive predictive values of 24.1%, 14.1%, and 14.3%, respectively. PAPP-A <5th percentile (OR 2.3 95% CI 1.1-4.7) and nuchal translucency >99th percentile (OR 3.5, 95% CI 1.1-11.3) were associated with increased risk of preterm delivery before 34 weeks. Increased risk at screening for trisomy 21 and 18 identified 16 of the 29 other chromosomal abnormalities (55%). Low free beta-hCG, low PAPP-A, and increased nuchal translucency were all associated with an increased rate of fetal abnormality. CONCLUSION: Extreme values of first-trimester free beta-hCG, PAPP-A, and nuchal translucency are all associated with adverse outcomes. The especially high predictive value for IUGR of PAPP-A levels below the 1st percentile suggests that patients within this group may benefit from increased surveillance for this condition.     

Combined measurement of fetal nuchal translucency, maternal serum free beta-hCG, and pregnancy-associated plasma protein A for first-trimester Down's syndrome screening.

PURPOSE: It has been proposed that first-trimester Down's syndrome screening has a higher detection rate compared to second-trimester biochemical screening. This study investigated the accuracy of Down's syndrome screening during gestational weeks 10 to 13 using the combination of fetal nuchal translucency (NT) measurement with maternal serum concentrations of free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A). METHODS: A total of 1,514 women with singleton pregnancies were enrolled in this study. Fetal NT was measured using the criteria published by the Fetal Medicine Foundation. Maternal serum concentrations of free beta-hCG and PAPP-A were determined by microtiter-plate ELISA. Down's syndrome risk was calculated using multivariate Gaussian distribution and Alpha software. RESULTS: Seventeen (1.12%) of the 1514 screened pregnancies had a fetal NT of at least 3 mm, and 41.2% of these had a poor pregnancy outcome, including four fetal aneuploidies. The odds of a fetal aneuploidy when the NT was greater than 2.0 multiples of median (MoM) was 90, when serum PAPP-A concentration was less than 0.45 MoM, it was 8.6, and when serum free beta-hCG concentration was greater than 2.2 MoM, it was 4.7. Using a risk cut-off level of 1 in 400, nine of 10 fetal aneuploidies were identified with a 4.7% false-positive rate, including two with trisomy 21, one with trisomy 18, and three with Turner's syndrome. CONCLUSIONS: This study demonstrated that Down's syndrome screening using the combined test in the first trimester had a higher detection rate than that of serum screening in the second trimester. Implementation of NT measurement in the first trimester provides substantial advantages for Down's syndrome detection and early diagnosis of fetal structural abnormalities.     

Pregnancy-associated plasma protein A, free beta-hCG, nuchal translucency, and risk of pregnancy loss

OBJECTIVE: To estimate the likelihood of clinical early and late pregnancy loss as a function of first-trimester maternal serum analytes and fetal nuchal translucency measurements. METHODS: Study subjects were recruited for a National Institute of Child Health and Human Development-sponsored multicenter cohort study initially designed to study the detection of Down syndrome during the first trimester of pregnancy. The cohort consisted of women who had a live fetus between 10 and 14 weeks of gestation and had no significant vaginal bleeding. Women with prior fetal trisomy (T21/18) and those with structural or chromosomal abnormalities in the index pregnancy were excluded. First-trimester screening consisted of pregnancy-associated plasma protein A (PAPP-A), free beta-hCG, and nuchal translucency. Pregnancy loss rates in women with various levels of PAPP-A, free beta-hCG, or nuchal translucency (less than 1st, less than 5th, more than 95th, and more than 99th percentile) were compared with losses in women with normal values (5th to 95th percentile). RESULTS: The mean gestational age at screening of 7,932 women meeting study criteria was 12.1 weeks. Loss rates were only 0.36% at less than 20 weeks after normal free beta-hCG, PAPP-A, and nuchal translucency. Conversely, low levels of PAPP-A and free beta-hCG as well as increased nuchal translucency were individually associated with increased early loss. These associations persisted after controlling for maternal age and race using logistic regression analysis. CONCLUSION: Normal values of PAPP-A, free beta-hCG, and nuchal translucency are associated with a very low risk of pregnancy loss at less than 20 weeks.     

First trimester maternal serum free beta human chorionic gonadotrophin and pregnancy associated plasma protein A as predictors of pregnancy complications

Objective To examine the value of first trimester maternal serum free β human chorionic gonadotrophin (β hCG) and pregnancy associated plasma protein A (PAPP-A) as predictors of pregnancy complications.
Design Screening study.
Setting Antenatal clinics.
Population Singleton pregnancies at 10–14 weeks of gestation.
Methods Maternal serum free β hCG and PAPP-A were measured at 10–14 weeks of gestation in 5584 singleton pregnancies. In the 5297 (94.9%) pregnancies with complete follow up free β hCG and PAPP-A were compared between those with normal outcome and those resulting in miscarriage, spontaneous preterm delivery, pregnancy induced hypertension or fetal growth restriction and in those with pre-existing or gestational diabetes.
Results Maternal serum PAPP-A increased and β hCG decreased with gestation. The multiple of median maternal serum PAPP-A was significantly lower in those pregnancies resulting in miscarriage, pregnancy induced hypertension, growth restriction and in those with pre-existing or gestational diabetes mellitus, but not in those complicated by spontaneous preterm delivery. The level was < 10th centile of the reference range in about 20% of the pregnancies that subsequently resulted in miscarriage or developed pregnancy induced hypertension or growth restriction, and in 27% of those that developed gestational diabetes. Maternal serum free β hCG was < 10th centile of the reference range in about 15% of the pregnancies that subsequently resulted in miscarriage or developed pregnancy induced hypertension or growth restriction, and in 20% of those that developed gestational diabetes.
Conclusion Low maternal serum PAPP-A or β hCG at 10–14 weeks of gestation are associated with subsequent development of pregnancy complications.     

A comparison between maternal serum free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein A levels in first-trimester twin and singleton pregnancies

OBJECTIVES: To determine the levels of first-trimester free beta-human chorionic gonadotrophin (free betahCG), pregnancy-associated plasma protein A (PAPP-A) and nuchal translucency (NT) in twin pregnancies. METHODS: The study included 93 patients with twin pregnancy and 4,977 with singletons who underwent first-trimester testing using free betahCG, PAPP-A and NT at 10-13 weeks of gestational age. RESULTS: In twin pregnancies, the maternal serum free betahCG level was 2.18 higher and the PAPP-A level was 2.38 higher than in singleton pregnancies. These marker levels were significantly higher than the expected 2.0 multiples of the median (MoM). In contrast, NT values did not differ between twins and singletons. CONCLUSION: These data may be used to establish first-trimester combined screening for twin pregnancies.     

Evaluation of pregnancy-associated plasma protein A (PAPP-A) and free beta subunit of human chorionic gonadotropin (beta hCG) levels and sonographic assesement of fetal nuchal translucency (NT) in singleton pregnancies between 11 and 14 weeks of gestation--Polish multi-centre research

Evaluation of pregnancy-associated plasma protein A (PAPP-A) and free beta subunit of human chorionic gonadotropin (beta hCG) levels and sonographic assessment of fetal nuchal translucency (NT) in singleton pregnancies between 11 and 14 weeks of gestation--Poland's multi-centers research. OBJECTIVES: Pregnancy-associated plasma protein A has been reported to be low in Down syndrome affected pregnancies during the first trimester of pregnancy. Enlarged nuchal translucency (NT) is observed in about 80% of fetuses affected with chromosomal abnormalities and congenital heart defects (CHD). MATERIAL AND METHODS: The aim of this study were to determine value and the medians of free beta-human chorionic gonadotropin (beta-hCG) and pregnancy associated plasma protein-A (PAPP-A) and nuchal translucency thickness in the first trimester in a prospective study of a non-selected Polish population. RESULTS: All examinations have been performed according to the Fetal Medicine Foundation (FMF) rules. We have included 800 women between 11 weeks 0 days and 13 weeks 6 days gestation into a biochemical examination. Women booked into the clinic were offered screening, using a combination of maternal serum free beta-hCG and pregnancy-associated plasma protein-A (PAPP-A) and fetal nuchal translucency thickness. The maternal serum were measured using the Kryptor analyzer (Brahms Diagnostica). All pregnant women have been divided into 2 groups younger than (first group) and older than (second group) 35 years of age. CONCLUSIONS: Nomogrames for free beta-hCG and PAPP-A levels in physiological pregnancy between 11(+0) and 13(6) weeks were determined in the examined population. A positive correlation between PAPP-A and CRL levels, as well as a weak negative correlation between free beta-hCG and CRL, were demonstrated.     

Maternal serum free-beta-chorionic gonadotrophin, pregnancy-associated plasma protein-A and fetal nuchal translucency thickness at 10-13(+6) weeks in relation to co-variables in pregnant Saudi women

OBJECTIVE: To establish normative values and distribution parameters of first-trimester screening markers, namely, fetal nuchal translucency (NT), maternal serum free beta-human chorionic gonadotrophin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A), at 10 to 13(+6) weeks of gestation in Saudi women and to evaluate the effect of co-variables including maternal body weight, gravidity, parity, fetal gender, twin pregnancy, smoking and ethnicity on these markers. METHODS: A cohort of Saudi women (first cohort n = 1616) with singleton pregnancies prospectively participated in the present study, and fetal NT together with maternal serum free beta-hCG and PAPP-A were determined at 10 to 13(+6) weeks of gestation. The distribution of gestational age-independent multiples of the median (MoM) of the parameters was defined and normative values were established, and correction for maternal body weight was made accordingly. The influence of various co-variables was examined using the data collected from the first and the second (n = 1849) cohorts of women and 62 twin pregnancies, and compared with other studies. RESULTS: All markers exhibited log-normally distributed MoMs. Gestational age-independent normative values were established. Maternal body weight was corrected, particularly for maternal free beta-hCG and PAPP-A using standard methods. Fetal NT showed a negative relationship with increasing gravidity (r = -0.296) or parity (r = -0.311), whereas both free beta-hCG and PAPP-A exhibited a significant positive relationship. There was a significant increase in the MoM of free beta-hCG in female fetuses. Smoking decreased MoM values of free beta-hCG (by 14.6%; P < 0.01) and PAPP-A (by 18.8%; P < 0.001). Twin pregnancy showed significant increases in MoM values of free beta-hCG (by 1.87-fold) and PAPP-A (by 2.24-fold), with no significant changes in fetal NT MoM values. Fetal NT MoM values were lower in Africans and Asians but higher in Orientals, as compared to Saudi women (P < 0.05; in each case). MoM values (body weight-corrected) of free beta-hCG were 25.2% higher in Africans and 19.4% higher in Orientals but 6.8% lower in other Arabian and Asian (by 5.8%) women as compared to Saudi women (P < 0.05; in each case). CONCLUSIONS: The normative values and distribution parameters for fetal NT, maternal serum free beta-hCG and PAPP-A were established in Saudi singleton pregnancies, the maternal body weight together with smoking, twin pregnancy and ethnicity being important first-trimester screening co-variables. Gravidity, parity and fetal gender are also considered to influence one or more of the first-trimester markers examined.     

Circulating levels of pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotrophin (hCG) in intrauterine and extrauterine pregnancies

Summary. Pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotrophin (hCG) have been measured in the plasma of pregnant and non-pregnant women attending the outpatient clinic for suspicion of pregnancy. The plasma concentrations obtained were grouped into intrauterine or extrauterine pregnancies and compared with values obtained in non-pregnant patients with similar periods of amenorrhoea. Patients with ectopic pregnancies had slightly lower PAPP-A levels and significantly lower hCG concentrations than those in women with normal intrauterine pregnancies. Non-pregnant women had very low hCG and PAPP-A levels compared with those in pregnant patients. These data suggest that in patients with extrauterine pregnancies the poorly sustained ectopic trophoblast is unable to produce normal concentrations of hCG and probably PAPP-A and that the slightly diminished levels of PAPP-A in ectopic pregnancies might be derived from a decidual production.     

The pregnancy-associated plasma protein A and insulin-like growth factor system in response to cigarette smoking

Objective: Maternal smoking during pregnancy is associated with a reduction in birth size but the mechanism by which this occurs still remains unclear. The purpose of this study was to evaluate the effect of tobacco smoking on concentrations of pregnancy-associated plasma protein A (PAPP-A), insulin-like growth factor I (IGF-I), II (IGF-II) and binding proteins BP-3 and BP-4 in pregnant women and correlations between these parameters. Methods: Sixty healthy pregnant women were divided into smoking and tobacco-abstinent group according to results of serum cotinine concentration. The current smokers were defined as those who had smoked five or more cigarettes per day during pregnancy. Results: The mean serum concentrations of PAPP-A, IGF-I and IGF–II were significantly lower in smoking than in non-smoking pregnant women (p < 0.01). The level of PAPP-A correlated positively with the IGF-II concentration in both studied group (non-smoking: r = 0.54; p < 0.001; smoking: r = 0.40; p < 0.05). In tobacco-abstinent group negative correlation between IGF-II and IGFBP-4 concentrations was found (r = ?0.35; p < 0.05). Conclusion: Tobacco smoking during pregnancy decreases the pregnancy-associated plasma protein A and insulin growth factors I and II levels. The correlation between PAPP-A and IGF-II may suggest function of this protein as a protease and regulator in the IGF system.     

Second trimester maternal serum beta human chorionic gonadotrophin and pregnancy outcome.

The aim of this prospective, controlled study was to examine the relation between second trimester maternal serum beta human chorionic gonadotrophin (HCG) and birthweight. The study population consisted of 192 women with maternal serum betaHCG > or = 3.5 multiple of the median and a control group with the same number of women with maternal serum betaHCG < or = 2.0 multiple of the median. There was no difference in birthweight and other pregnancy outcomes between the two groups. When used prospectively, elevated betaHCG in the mid-trimester is not a predictor for intrauterine growth restriction or other pregnancy complications.     

The impact of assisted reproductive technology on the association between first-trimester pregnancy-associated plasma protein a and human chorionic gonadotropin and adverse pregnancy outcomes

We evaluated the impact of assisted reproductive technology (ART) on the association between first-trimester pregnancy-associated plasma protein A (PAPP-A) and human chorionic gonadotropin (β-hCG) and adverse pregnancy outcomes. PAPP-A and β-hCG levels were obtained between 11 and 13 (6)/ (7) weeks' gestation and converted to multiples of the median (MoM). MoM < 5th percentile was defined as low PAPP-A or β-hCG and those > 90th percentile as high. Adverse outcomes included small-for-gestational-age (SGA) infants, preeclampsia, pregnancy loss, and preterm delivery (PTD). Univariate and multivariate analyses were used to estimate the association. Of 4000 women meeting the inclusion criteria, 265 (7.6%) pregnancies were conceived by ART. ART pregnancies with low PAPP-A had a higher risk of having an SGA infant (odds ratio [OR] = 4.1, 95% confidence interval [CI] 1.2, 14.0) or PTD < 32 weeks (OR = 5.3, 95% CI 1.5, 18.6) compared with non-ART pregnancies with low PAPP-A (OR = 2.8, 95% CI 1.7, 4.7; OR = 3.9, 95% CI 2.1, 7.0, respectively). High PAPP-A was associated with pregnancy loss (OR = 6.1, 95% CI 1.1, 33.7) in ART pregnancies. Low β-hCG was associated with increased risk for PTD only in ART pregnancies (OR = 8.3, 95% CI 1.9, 35.9) for PTD < 37 weeks (OR 6.1, 95% CI 1.6, 23.0) for PTD < 35 weeks and (OR = 10.8, 95% CI 2.7, 43.7) for PTD < 32 weeks. High β-hCG was associated with increased risk for SGA (OR = 1.6, 95% CI 1.0, 2.5) and PTD < 37 weeks (OR = 1.4, 95% CI 1.0, 1.9) in non-ART pregnancies. The association between PAPP-A and β-hCG with adverse pregnancy outcomes is influenced by the mode of conception.     

In vitro secretory patterns of human chorionic gonadotrophin, placental lactogen and pregnancy-specific beta 1-glycoprotein

The control of secretion of the placental hormones human chorionic gonadotrophin (hCG) and human placental lactogen (hPL), and the trophoblastic protein pregnancy-specific beta-glycoprotein (SP1), is not well understood. During pregnancy, the hCG concentrations peak in the first trimester then decrease, while hPL and SP1 increase steadily throughout gestation. In order to determine whether the discordance between hCG secretion and that of hPL and SP1 observed in vivo also occur in vitro, we cultured placental explants with and without dibutyryl cyclic AMP (dbcAMP) and theophylline. Between 5 and 12 explants were used for each treatment in each experiment. The concentration of the proteins secreted into the media each day was measured by specific radioimmunoassays. The quantities of hPL and SP1 secreted per day declined in a parallel fashion after 24 hours under both basal and dbcAMP-stimulated conditions. The hCG output progressively decreased in the unstimulated cultures until 48 hours, at which time an increase in hCG secretion was observed. The dbcAMP-stimulated placentae significantly increased their hCG output at both 48 and 72 hours. These data show that hCG secretion is regulated differently from that of hPL and SP1. The results do not negate the possibility that term placental tissue may contain an inhibitor of hCG release that is removed by experimental manipulation in vitro.     

Maternal serum pregnancy-associated plasma protein-A and free beta-human chorionic gonadotrophin in pregnancies conceived with fresh and frozen-thawed embryos from in vitro fertilization and intracytoplasmic sperm injection

OBJECTIVE: Maternal serum pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotrophin (beta-hCG) are useful markers in the screening of Down syndrome in the first trimester. We investigated the effect of intracytoplasmic sperm injection (ICSI), freezing and thawing of embryos on the levels of these two analytes in assisted reproduction pregnancies. METHODS: We recruited 149 women who conceived after assisted reproduction with fresh embryos (92 from conventional IVF and 57 from ICSI), 85 women who conceived with frozen-thawed embryos (54 from conventional IVF and 31 from ICSI) and 401 women with spontaneous conceptions as controls. The concentrations of PAPP-A and free beta-hCG were measured between 10 and 14 weeks and were converted to multiples of medians (MoM) for comparisons. RESULTS: Median PAPP-A MoMs were significantly reduced in ICSI pregnancies in the fresh and frozen-thawed embryo subgroups (0.70 and 0.66 MoM respectively) and in the IVF fresh embryo subgroups (0.83 MoM), as compared to controls (1.00 MoM). Free beta-hCG MoM was significantly reduced in the IVF fresh embryos subgroup (0.87 MoM), but not in the other three subgroups. CONCLUSION: Further studies for exploring the underlying pathophysiology and adjustment in the marker levels for screening of Down syndrome are warranted in pregnancies conceived after assisted reproduction.