Does ultrasound examination render biochemical tests obsolete in the prediction of early pregnancy failure?

Predictive value of pregnancy-associated plasma protein-A in relation to fetal loss: A systematic review and meta-analysis

Background

For a woman with bleeding and threatened abortion, ultrasound scan is done to confirm the viability of the fetus; however, 10-15% of the embryos are eventually aborted. Distinguishing between women with good and poor prognosis can be a helpful approach.

Objective

This study aimed to review the predictive value of Pregnancy-associated Plasma Protein A (PAPP-A) in relation to the diagnosis of fetal loss.

Materials and Methods

The articles published in multiple databases including Web of Science, PubMed, MEDLINE, Scopus, and Persian databases such as ISC, Magiran, and IranMedx were searched for articles published until May 2019. MeSH terms was used for searching the databases including fetal loss OR pregnancy loss OR abortion OR miscarriage with the following word using AND; Pregnancy-Associated Plasma Protein-A OR PAPP-A. Two reviewers extracted data and recorded them in a pre-defined form and assessed the quality of articles using the Newcastle-Ottawa tool. Meta-analysis was done using the Comprehensive Meta-Analysis/2.0 software and MetaDisc.

Results

A total number of 16 studies were eligible for the qualitative data synthesis, out of which 8 studies were included in the meta-analysis. All studies had high and medium quality. The forest plot analysis showed a sensitivity of 57% (95% CI: 53-63%), a specificity of 83% (95% CI: 80-85%), a positive likelihood ratio of 3.52 (95% CI: 2.44-5.07), a negative likelihood ratio of 0.54 (95% CI: 0.37-0.79), and a diagnostic odds ratio of 6.95 (95% CI: 3.58-13.50).

Conclusion

PAPP-A cannot be recommended on a routine basis for predicting fetal loss and still further research with a combination of other biomarkers is required.

Biomarkers of oxidative stress in pregnant women with recurrent miscarriages

Background

The aim of this study was to evaluate the markers of oxidative stress (OS), as well as the magnesium (Mg) concentration, pregnancy-associated plasma protein A (PAPP-A) and human chorionic gonadotropin (β-hCG) values in patients with previous recurrent miscarriages, with the purpose of comparing the level of OS with normal pregnancy.

Methods

The study was conducted as a prospective study, which included a total of 95 pregnant women divided into two groups. In the study group (n = 35), there were women with at least three consecutive previous miscarriages. The control group (n = 60) consisted of healthy pregnant women without previous miscarriages and complications in pregnancy. Blood samples were taken between the 11th and 14th weeks of gestation, and the values of superoxide dismutase (SOD-1), glutathione peroxidase (GSH-Px) and total antioxidant status (TAS) in the serum, as well as the Mg concentration, PAPP-A and β-hCG values were determined.

Results

The values of SOD and GHS-Px were statistically higher in the study group, while the values of TAS were statistically significantly higher in the control group. The values of the Mg concentration were statistically significantly higher in the control group, while the values of β-hCG were statistically significantly higher in the study group. When the study group was divided into subgroups according to the outcome of pregnancy, there were statistical differences in the level of GSH-Px, SOD between miscarriages and the term delivery group, as well as in the Mg concentration between miscarriages and the term delivery group and between the term and preterm delivery groups. Higher values of SOD and GHS-Px, and lower values of TAS and Mg concentration could be used as markers for the prediction of spontaneous miscarriages.

Conclusions

The results of this research indicated higher OS and exhaustion of antioxidant mechanisms in early pregnancy in a group with recurrent miscarriages. Also, lower values of serum Mg concentration could be one of the markers for the prediction of spontaneous miscarriages.

Role of serum biomarkers in the prediction of outcome in women with threatened miscarriage: a systematic review and diagnostic accuracy meta-analysis

BACKGROUND

Threatened miscarriage affects one in five women and is associated with significant emotional distress. The uncertainty around the prognosis of threatened miscarriage makes it equally challenging to the healthcare professionals. Various biochemical markers have been investigated in the past to predict the outcome of threatened miscarriage; however, the results have been conflicting. Therefore, we have conducted a systematic review and meta-analysis to determine the diagnostic accuracy of biochemical markers in predicting the outcome in women presenting with threatened miscarriage.

METHODS

This is a systematic review and meta-analysis of prospective studies that investigated biochemical markers to determine outcomes for women with threatened miscarriage at 5-23 weeks gestational age. Electronic databases were searched up to June 2015 and study quality assessment was performed using QUADAS-2 (Quality Assessment for Diagnostic Accuracy Studies-2: A Revised Tool) for evaluating the diagnostic accuracy studies. Statistical analysis was performed using the Cochrane systematic review software.

RESULTS

A total of 19 studies were included in the qualitative data synthesis of which 15 (including 1263 women) were eligible for the meta-analysis. The review highlights the role of biochemical markers serum progesterone, hCG, pregnancy associated plasma protein A, estradiol and cancer antigen 125 (CA 125) in the prediction of outcome in women with threatened miscarriage. Interestingly, serum CA 125 appears to be the most promising marker (n = 648 women in seven studies), whereas serum progesterone and hCG are less useful once fetal viability is established. The summary receiver operating characteristics for CA 125 showed a sensitivity of 90% (95% confidence interval (CI) 83-94%), specificity of 88% (95% CI 79-93%), positive likelihood ratio of 7.86 (95% CI 4.23-14.60) and negative likelihood ratio of 0.10 (95% CI 0.06-0.20). The inverse of negative likelihood ratio was 9.31 (95% CI 5-17.1) indicating that a negative test is likely to identify those who are likely to continue with the pregnancy. Serum estradiol was the next best marker with a sensitivity of 45% (95% CI 6-90%), a specificity of 87% (95% CI 81-92%), a positive likelihood ratio of 3.72 (95% CI 1.01-13.71) and a negative likelihood ratio of 0.62 (95% CI 0.20-1.84).

CONCLUSIONS

In women with threatened miscarriage, serum CA 125 has high predictive value in identifying pregnancies that are 'likely to continue', whereas the most commonly used biomarkers of serum hCG and progesterone are not useful in predicting outcome of a pregnancy with a viable fetus. Other markers such as inhibin A and a combination of markers need to be investigated to hopefully improve the prediction of outcome in women with threatened miscarriage.

Maternal serum hormone concentrations for prediction of adverse outcome in threatened miscarriage

Many serum markers have been investigated in attempts to predict the outcome of pregnancy in the first trimester, with varying degrees of success. The objective of this study was to investigate whether they can be related to pregnancy outcome in women presenting with first trimester threatened miscarriage. A cohort study of women attending the Early Pregnancy Unit of a London teaching hospital was studied. A total of 122 women presenting with bleeding in the first trimester and an ongoing pregnancy, and 33 women undergoing termination of pregnancy, were recruited. The main outcome measures were gestation at delivery, birth weight and the incidence of adverse pregnancy outcome. Inhibin A, activin A, human chorionic gonadotrophin (HCG), pregnancy-associated plasma protein-A and follistatin concentrations were all significantly lower in women who subsequently miscarried when compared with live births. Serum HCG concentrations were significantly higher in cases of threatened miscarriage compared with controls (P = 0.0009). Logistic regression analysis indicated that inhibin A alone provided the best predictor for first trimester miscarriage. This pilot study suggests that placental hormone concentrations could be useful in predicting adverse pregnancy outcome in women presenting with threatened miscarriage. Inhibin A was best at predicting the likelihood of subsequent miscarriage in this group.

Pregnancy-associated plasma protein-A polymorphism and the risk of recurrent pregnancy loss

Pregnancy-associated plasma protein-A (PAPP-A)/insulin-like growth factor-binding protein-4 (IGFBP4) protease is a member of the metzincin family of metalloproteases, known as a sensitive biomarker of adverse pregnancy outcomes. Recently, a missense A/C (Tyr/Ser) polymorphism (dbSNP: rs7020782) in the PAPPA gene has been reported. To examine the association between recurrent pregnancy loss (RPL) and this polymorphism, a case-control study of 215 cases with two or more pregnancy losses (PLs) and 420 fertile controls was performed. Genotyping of the PAPPA polymorphism was determined by allelic discrimination using fluorogenic probes and the 5' nuclease assay. Sixty-nine cases (32.1%) were heterozygous and 11 cases (5.1%) were homozygous for the C allele of PAPPA; the respective figures were 127 (30.2%) and 11 (2.6%) in the controls. Women carrying the C allele had a tendency to increased risk of RPL (AA genotype [reference]; AC genotype: odds ratio [OR], 1.17; 95% confidence interval [CI], 0.82-1.68; CC genotype: OR, 2.06; 95% CI, 0.87-4.90), but it was not significant. Women with three or more PLs had a similar tendency (AA genotype [reference]; AC genotype: OR, 1.04; 95% CI, 0.66-1.64; CC genotype: OR, 2.20; 95% CI, 0.82-5.91). The risk of RPL with at least one PL after 9 weeks' gestation significantly increased in women carrying the C allele (AA genotype [reference]; AC genotype: OR, 1.54; 95% CI, 0.95-2.49; CC genotype: OR, 2.83; 95% CI, 1.00-8.05; AC+CC genotypes: OR, 1.65; CI, 1.04-2.62). This is the first report on the PAPPA gene polymorphism in women with RPL, demonstrating some association between the investigated polymorphism and the risk of RPL.

Hormonal monitoring of the first trimester of pregnancy

The hormonal changes and maternal adaptations of human pregnancy are among the most remarkable phenomena in nature. Endocrinologic parameters in the early gestation period have been used to predict abnormal pregnancies and to identify fetuses that have chromosomal aberrations. This article focuses on the changes in hormones that are secreted by the maternal-fetal-placental unit that are unique for the first trimester of pregnancy and their impact on clinical outcome.

Low levels of pregnancy-associated plasma protein-A in asymptomatic women destined for miscarriage

In an asymptomatic cohort, serum pregnancy-associated protein-A (PAPP-A) levels among women destined to miscarry were 14% of those seen with ongoing pregnancies. Levels were as low 3 weeks before diagnosis as on the day of diagnosis, suggesting that PAPP-A levels might predict future miscarriage.

Decreased first trimester PAPP-A is a predictor of adverse pregnancy outcome

OBJECTIVE

Low levels of maternal serum pregnancy associated plasma protein-A (PAPP-A) have been linked to chromosome anomalies such as trisomy 21, 13 and 18, triploidy and sex chromosome aneuploidy. Low levels of PAPP-A have also been implicated in spontaneous miscarriage. The purpose of this study was to evaluate whether low levels of first trimester PAPP-A are predictive of other adverse pregnancy outcomes.

STUDY DESIGN

The study included patients with singleton pregnancies who underwent combined first trimester screening using nuchal translucency (NT) and maternal serum free beta-human chorionic gonadotrophin (free beta-hCG) and PAPP-A at 10-13 weeks' gestation. Patients with chromosome aberrations or fetal anomalies were excluded. Serum marker levels were expressed as gestational age-specific multiples of the median (MoMs). The incidences of various adverse pregnancy outcomes (spontaneous preterm labor, fetal growth restriction (FGR), proteinuric and non-proteinuric pregnancy induced hypertension (PIH), intrauterine fetal demise, oligohydramnios, spontaneous miscarriage and placental abruption) were evaluated, according to maternal PAPP-A MoM levels.

RESULTS

Of the 1622 patients in the study, pregnancy complications were observed in 184 (11.3%). Patients with PAPP-A < or =0.25 MoM had significantly higher rates of FGR (RR = 3.12), proteinuric PIH (RR = 6.09), spontaneous miscarriage (RR = 8.76). No statistically significant differences were noted for other adverse outcomes evaluated Women with PAPP-A < or =0.50 MoM also had significantly higher rates of FGR (RR = 3.30) and spontaneous miscarriage (RR = 3.78).

CONCLUSIONS

We conclude that decreased levels of first trimester maternal serum PAPP-A are predictive not only of chromosome anomalies but also of adverse pregnancy outcome.

Accuracy of single measurements of pregnancy-associated plasma protein-A, human chorionic gonadotropin and progesterone in the diagnosis of early pregnancy failure

BACKGROUND

Circulating human chorionic gonadotropin (hCG) and progesterone are commonly used as markers of abnormal pregnancies. Previous studies have shown that pregnancy-associated plasma protein-A (PAPP-A) was also depressed in extrauterine pregnancies (EUP). Previously, PAPP-A was measured with polyclonal antibodies which were later shown to recognise also the pro-form of major basic protein (pro-MBP).

OBJECTIVE

To evaluate the clinical usefulness of PAPP-A measurements in early pregnancy.

STUDY DESIGN

Circulating PAPP-A, hCG and progesterone were measured in patients with EUP (n=68), abnormal intrauterine pregnancies (abIUP, n=31) and normal intrauterine pregnancies (nIUP, n=72). Gestational age was 30-70 days from the last menstruation.

RESULTS

For PAPP-A and hCG, a steep increase was observed from day 30 after last menstrual period onwards, this increase being much less important for abIUP and EUP. The values of PAPP-A and hCG were significantly decreased in abIUP and EUP, from 42 days after LMP onwards. There were no significant differences between abIUP and EUP. Progesterone concentration does not vary with amenorrhoea and was significantly lower in abIUP and EUP. Values in abIUP were significantly (P=0.02) lower compared with EUP for amenorrhoea above 42 days. ROC curves were constructed for amenorrhoea above 42 days. For a specificity of 99%, the sensitivity of PAPP-A, hCG and progesterone were 64.5, 93.3 and 76%, respectively. The threshold values were 14.3mIU/l, 10,400IU/l and 10.1ng/ml for PAPP-A, hCG and progesterone.

CONCLUSION

We confirm the decrease of PAPP-A concentrations in pregnancy failure, but hCG and progesterone remain the best clinical tools.

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 beta human chorionic gonadotrophin (beta 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 beta hCG and PAPP-A were measured at 10-14 weeks of gestation in 5,584 singleton pregnancies. In the 5,297 (94.9%) pregnancies with complete follow up free beta 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 beta 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 beta 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 beta hCG at 10-14 weeks of gestation are associated with subsequent development of pregnancy complications.

Women's opinions and the implications of first- versus second-trimester screening for fetal Down's syndrome

Two groups of pregnant women were questioned regarding their opinions on serum screening for Down's syndrome in the first trimester of pregnancy. One group comprised 83 women attending our antenatal clinic who were questioned at the time of the existing second-trimester screening test. Seventy-six per cent of those who participated in the second-trimester screening programme would have preferred the test to have been in the first trimester, mainly because of the easier termination of pregnancy and/or the earlier reassurance provided. The remaining 24 per cent could see no advantage in the earlier time frame. Of the 49 women who had declined second-trimester screening, only two would have participated in screening had it been in the first trimester. The other group comprised those women attending our antenatal diagnosis clinic who were considering chorionic villus sampling (CVS). Forty-four per cent of these women would have allowed serum screening in the first trimester to influence their decision as to whether to undergo definitive prenatal diagnostic testing. In general, those women who made use of second-trimester serum screening would also do so in the first trimester. Those who declined the existing screening programme would also decline first-trimester screening. Many women currently deciding to undergo CVS would allow a first-trimester screening test to influence their decision.

Serum concentrations of human chorionic gonadotrophin and immunoreactive inhibin in early pregnancy and recurrent miscarriage: a longitudinal study

Serum concentrations of immunoreactive inhibin (ir-inhibin) and human chorionic gonadotrophin (HCG) have been measured during the first trimester in a longitudinal study of pregnant women attending a recurrent miscarriage clinic. In 30 singleton pregnancies (Group 1) that continued successfully to term, the median concentration of ir-inhibin initially declined from 1,140 pg/mL at week 4-5 then rose back to comparable values between weeks 7 and 10 but to decline again to reach the significantly lower level of 840 pg/mL (p < 0.01) at week 15-16. Serum levels of HCG showed the classical profile of normal pregnancy reaching a median peak value of 65,600 IU/L (1st IRP) at week 8-9. In 7 pregnancies that miscarried but earlier had evidence on ultrasound of an active fetal heart, HCG levels in the first 9 weeks were consistently below the 10th percentile for Group 1 pregnancies (p < 0.001). Levels of ir-inhibin were also suppressed but to a lesser extent. In 6 of 7 a fetal pregnancies, HCG levels during the first 9 weeks were again markedly subnormal. The levels of ir-inhibin varied between high normal and subnormal. In none of the pregnancy groups was a correlation found between ir-inhibin and HCG concentrations. In a single pregnancy with an anencephalic fetus, while levels of ir-inhibin and HCG were not depressed, peak values were not reached until week 12. The study shows that the level of ir-inhibin in the maternal serum in early pregnancy is of little value as a prognostic indicator of pregnancy outcome. It confirms that a subnormal HCG level is a useful predictor of early pregnancy failure.

Trophoblast antigen levels in the first trimester of a trisomy 22 pregnancy

We report trophoblast antigen (pregnancy-associated plasma protein-A, PAPP-A; free beta-human chorionic gonadotrophin, F beta hCG) expression in a trimosy 22 pregnancy. Maternal concentrations of these antigens were depressed prior to detection of abnormalities by ultrasonography. Immunohistochemical findings were consistent with depressed marker expression.

The role of trophoblast dysfunction in the aetiology of miscarriage

OBJECTIVE

To investigate the endocrine changes associated with spontaneous miscarriage after fetal heart activity has been demonstrated.

DESIGN

Prospective study during the first trimester of pregnancy comparing the circulating levels of human chorionic gonadotrophin (hCG), Schwangerschaft protein 1 (SP-1), pregnancy-associated plasma protein A (PAPP-A), oestradiol (E2), and progesterone (P), and fetal growth (crown-rump length [CRL] and gestational sac volume [GSV]) in women who miscarried after the identification of fetal heart activity with those of normal singleton and twin pregnancies achieved following in vitro fertilisation (IVF) and embryo transfer (ET).

SETTING

The Assisted Conception Unit of King's College Hospital, London.

SUBJECTS

Nine women who miscarried after demonstration of fetal heart activity, 52 normal singleton and 22 normal twin pregnancies.

INTERVENTIONS

Weekly blood tests and ultrasound assessments of CRL and GSV.

RESULTS

Four fetuses (all singleton) died between 9 and 12 weeks gestation (Group 1), and seven (three singleton and two twin) died between 16 and 20 weeks gestation (Group 2). In Group 1, both fetal growth and placental function, as assessed by serial measurements of CRL and GSV, and of serum levels of PAPP-A, SP-1 and hCG respectively, were reduced before fetal death. In Group 2, while fetal growth was maintained in all but one case, placental function was reduced in 4 of 5 women.

CONCLUSION

These findings suggest that there may be a relationship between trophoblast dysfunction and some forms of miscarriage. Furthermore, the pattern of the reduction in the circulating levels of the placental proteins in later miscarriages suggests that the function of specific cell types may be impaired.

A baboon model for pregnancy-associated antigens (PAPP-A, PP5, PP14)

By radioimmunoassays established on human derived antigens, PAPP-A, PP5 and PP14 immunoreactivity was detected in placental extracts and blood of pregnant baboons. None of the serial dilution curves suggested parallelism between respective human and baboon samples. Based on slopes of regressed logit-log transformed binding data, PAPP-A demonstrated the greatest degree of interspecies immunological crossreactivity. PP14 showed the least conservation of antigenic determinants. Physicochemical characterization on heparin, zinc chelate and bovine thrombin affinity matrices could not distinguish human from baboon-derived antigens. As in the human, baboon PAPP-A and PP5 were not detected in blood of male or non-pregnant animals. PP14 was detected in baboon follicular fluid, and only PP5 immunoreactivity was measured in culture media of baboon embryos. Of the three antigens, PAPP-A was detected in pregnant baboons at about 61 days gestation, that is, 4 weeks before PP5 and PP14. With the exception of PP14 which attained peak concentration at 118 days of pregnancy, PAPP-A and PP5 concentrations were greatest at term. In conjunction with physicochemical and immunological criteria, these physiological kinetics clearly support a role for developing a baboon model to serve for further studies into feto-maternal signals, particularly antigens such as PAPP-A and PP5.

Ultrasound and circulating placental protein measurements in complications of early pregnancy

Maternal serum levels of human chorionic gonadotrophin (hCG), Schwangerschaftsprotein 1 (SP1) and pregnancy-associated plasma protein A (PAPP-A) were measured in an unselected group of 624 women presenting with amenorrhoea and vaginal bleeding with or without abdominal pain to an emergency gynaecological ultrasound clinic. Abdominal sector scanning was used to assess uterine contents. Pregnancy was confirmed by ultrasound in 406 pregnancies. Histological confirmation was obtained in each case of pregnancy failure. A live fetus was demonstrated in 259 women of whom six subsequently miscarried; one of these had markedly depressed serum hCG and PAPP-A, but normal SP1 levels, and two had oligohydramnios. Of the 147 women without ultrasound evidence of fetal heart action 67 had a correct ultrasound diagnosis of anembryonic pregnancy. The predictive value of a depressed serum hCG level was 70% in this group, and 31% in samples taken at less than or equal to 7 weeks. The predictive value of a normal hCG level was 96%. In 34 women missed miscarriage was diagnosed readily by ultrasound; all but five had depressed hCG and PAPP-A levels. A clinical diagnosis of a complete or incomplete miscarriage was made in 45 women and easily confirmed by ultrasound. All of them had depressed hCG, SP1 and PAPP-A levels. These results indicate that the diagnostic value of ultrasound in threatened miscarriage is often better than that of biochemical tests.

Some endocrinological events associated with early pregnancy failure

Serial measurements of serum progesterone, oestradiol, human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) have been determined in 33 women experiencing early pregnancy failure and compared with the values of the same hormones in 72 healthy women having uncomplicated pregnancies. Steroid production by the corpus luteum seemed similar in both groups up to 6 weeks gestation but thereafter placental steroidogenesis was not evident in those women in whom spontaneous pregnancy losses occurred. Placental production of the two protein hormones, hCG and hPL, did take place, and whereas the circulating levels were not as high as in normal pregnancies, levels did usually increase before clinical evidence of miscarriage occurred. hCG was not a sensitive discriminator of subsequent failure. In these women there were no significant hormone differences between those with evidence of a fetus and those without.

Measurements of placental, decidual, and fetal proteins before and after chorionic villus sampling

Circulating placental [human chorionic gonadotrophin (hCG), Schwangerschafts protein 1 (SP1), pregnancy-associated plasma protein A (PAPP-A), decidual (pregnancy protein 12 (PP12), and fetal alphafetoprotein (AFP)] proteins were measured immediately before and within 1 h in 18 women undergoing diagnostic chorionic villus sampling (CVS) in the first trimester. An elevation of serum AFP levels was consistently seen, while fluctuations in excess of 10 per cent of the pre-CVS levels of SP1 and PP12 were seen in the majority of patients. Fluctuations in hCG and PAPP-A were consistently less than 10 per cent of pre-CVS values. Post-CVS changes in levels were not apparently associated with any feature of the technique, the pregnancy, or its outcome (one missed abortion). As feto-maternal haemorrhage is a common event, anti-D should be offered to rhesus-negative women undergoing CVS. In the prediction of subsequent miscarriage, only hCG and PAPP-A measurements should be considered.

Changes in circulating alphafetoprotein and human chorionic gonadotrophin following chorionic villus sampling

Chorionic villus sampling (CVS) is rapidly becoming established as a routine procedure for first-trimester fetal diagnosis. The technique can result in fetomaternal haemorrhage and this might sensitize Rhesus-negative mothers and on occasion lead to spontaneous abortion. Serial sampling indicates that there is a rapid rise in alphafetoprotein (AFP) levels following CVS; however, this is not reflected by raised levels at 16-18 weeks and does not influence the subsequent pregnancy outcome. Unlike AFP, alterations in hCG levels are small and variable. Anti-D prophylaxis for non-sensitized Rhesus negative mothers should be given after CVS and the procedure may be contra-indicated in patients who are already sensitized.

Pregnancy-specific and pregnancy-associated proteins in threatened abortion

Pregnancy sera (390) were taken between the 5th and 16th weeks of gestation, from subjects whose pregnancies were uneventful throughout the entire gestation period. In-house curves of first-trimester normal values (10th, 50th, 90th percentile) were established for human chorionic gonadotropin (hCG), human placental lactogen (hPL), pregnancy-specific beta 1-glycoprotein (SP-1), pregnancy-associated plasma protein A (PAPP-A), and pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) after the measurement of these proteins in the sera by immunoassay. Eighty sera from patients with threatened abortion were also obtained and the placental proteins mentioned above were determined. Values falling below the 10th percentile of the normal population were classified as positive (i.e., pathological) results; the others were considered negative. Based on the outcome of the pregnancy, the results were grouped into true positives (low value and lost pregnancy), false positives (low value and ongoing pregnancy), true negatives, and false negatives. The sensitivity, specificity, and the positive predictive value of each protein as an indicator for abortion were calculated. In terms of specificity hCG and SP-1 were good, whilst PAPP-A and hCG showed the highest sensitivity. The best predictive values were obtained from SP-1 and hCG. The results show that PAPP-A and SP-1 perform satisfactorily but that none of these proteins significantly improves on hCG.

Ultrasonic assessment of complications during first trimester of pregnancy

624 women were referred to an emergency gynaecological ultrasound clinic with a provisional diagnosis of threatened miscarriage based on a history of amenorrhoea and vaginal bleeding with or without abdominal pain. High-resolution abdominal sector scanning was used to assess fetal size and viability, as well as uterine and placental size, to identify features which might indicate imminent fetal death. In 158 women there was no evidence of pregnancy; 60 women had an ectopic pregnancy. In the remaining 406 women ultrasound examination correctly identified the underlying cause of vaginal bleeding at first presentation in all but the 6 who subsequently aborted. 3.9% of the patients had a second empty sac and 5.4% had an intrauterine haematoma; none of these women subsequently aborted. 2 patients had early-onset oligohydramnios and spontaneous abortion occurred in both.

Measurements of hCG and PAPP-A in uncommon types of ectopic gestation

Seven out of 54 women with ectopic gestation had uncommon features such as extra-tubal implantation or multiple intratubal pregnancy. Depressed levels (less than 10th centile) or apparent absence of circulating human chorionic gonadotrophin (hCG) and pregnancy-associated plasma protein A (PAPP-A) were seen respectively in 5 and 7 of 7 women studied. Normal levels of hCG were seen in two women, one with an abdominal and one with an angular pregnancy. These data suggest that the synthesis of placental proteins in ectopic pregnancies is independent of the site of implantation and the number of embryos. Measurements of maternal levels of the 2 placental proteins seem to be applicable as auxiliary diagnostic tests for ectopic pregnancy, regardless of the site of implantation.

Predictive value of plasma human chorionic gonadotrophin beta subunit in diagnosing ectopic pregnancy after in vitro fertilisation and embryo transfer

A study was conducted aimed at establishing a range of plasma concentrations of the beta subunit of human chorionic gonadotrophin that might predict ectopic pregnancy after in vitro fertilisation and embryo transfer. From May 1984 to February 1986, 161 consecutive pregnancies at the Monash University in vitro fertilisation unit were analysed by determining plasma beta human chorionic gonadotrophin concentrations between two and 10 weeks after oocyte collection. Eighty eight ongoing singleton pregnancies, 25 multiple pregnancies, 27 first trimester spontaneous abortions, 12 anembryonic pregnancies, and nine ectopic pregnancies resulted from these conception cycles. When compared with values for ongoing singleton pregnancies two weeks after oocyte collection plasma beta human chorionic gonadotrophin concentrations in ectopic pregnancies were significantly lower (p less than 0.05; Wilcoxon rank sum test). Two weeks after oocyte collection all plasma beta human chorionic gonadotrophin concentrations in the set of ectopic pregnancies were below 30.6 IU/l, which corresponded to the lower quartile (25th percentile) of beta human chorionic gonadotrophin concentrations in ongoing singleton pregnancies. The beta human chorionic gonadotrophin concentration corresponding to the lower quartile of ongoing singleton pregnancies at each week of gestation was used to derive the predictive value of various statistics in detecting ectopic pregnancy in patients after in vitro fertilisation. The sensitivity, specificity, predictive value of a positive result, predictive value of a negative result, and efficiency of a single plasma beta human chorionic gonadotrophin concentration in predicting ectopic pregnancy were 100%, 68.1%, 16.7%, 100%, and 70%, respectively, two weeks after oocyte collection. These results suggest that a single determination of the plasma beta human chorionic gonadotrophin concentration beginning 14 days after oocyte collection is clinically useful in predicting the outcome of pregnancy achieved by in vitro fertilisation. Ectopic pregnancy after in vitro fertilisation is more likely when beta human chorionic gonadotrophin concentration is below the lower quartile of values in ongoing singleton pregnancies achieved by the technique.

The prognostic value of HCG, PAPP-A, oestradiol-17 beta and progesterone in early human pregnancy

Four serum parameters were assayed weekly from the 4th to the 12th week of pregnancy and finally at 16 weeks, to assess their relative prognostic values for predicting pregnancy outcome. Of 85 pregnancies generated following treatment for infertility, 16 cases had blighted ova and subsequently aborted at a mean age of 9.9 +/- 0.5 weeks. Serum HCG concentrations differentiated (p less than 0.005) between ongoing pregnancies and blighted ova as early as the 4th week which was often several weeks in advance of clinical abortion. PAPP-A, oestradiol-17 beta and progesterone did not differentiate between the 2 groups until 7 weeks (p less than 0.005, p less than 0.001 and p less than 0.001 respectively). PAPP-A measurements detected ongoing pregnancies at week 4 (16.5 +/- 5 micrograms/l) but HCG remains the more sensitive diagnostic test. The lower limits of oestradiol-17 beta and progesterone for ongoing pregnancies were 670 pmol/l and 37 nmol/l respectively. The circulating concentrations of all 4 serum markers were unaffected by administration of medroxyprogesterone acetate from 6 to 16 weeks in both ongoing and aborting pregnancies.

Relation between pregnancy-associated plasma protein A (PAPP-A) in human peri-ovulatory follicle fluid and the collection and fertilization of human ova in vitro

In 42 patients, blood-free peri-ovulatory follicular fluid was aspirated from 86 follicles for estimation of pregnancy-associated plasma protein A (PAPP-A) and related to several variables associated with the fertilization of human ova in vitro. Follicle growth was stimulated by clomiphene citrate alone or in combination with human menopausal gonadotrophin (hMG) and ovulation was triggered by human chorionic gonadotrophin (hCG) except in six patients who had a spontaneous surge of luteinizing hormone (LH). PAPP-A was detected in 83 of the 86 follicles aspirated, ranging from 'undetectable' to 1044 micrograms/l. The concentration of PAPP-A was statistically significantly correlated with increasing follicle size, follicular oestradiol-17 beta concentration and oocyte recovery. At PAPP-A concentrations of greater than 200 micrograms/l, there was no correlation noted with the ability of the ovum to be fertilized, to cleave, or between PAPP-A levels in follicles from pregnant and non-pregnant cycles. There was no significant difference in the mean PAPP-A concentration for the two stimulation regimens, but concentrations were greater in follicular fluid from patients who surged spontaneously (P less than 0.001). It appears PAPP-A levels may provide an index of follicle maturity but not of the pregnancy potential of the ovum.

Monitoring of postimplantation embryo viability following successful in vitro fertilization and embryo transfer by measurement of placental proteins

Serum levels of pregnancy-associated plasma protein A (PAPP-A), human chorionic gonadotropin (hCG), and pregnancy-specific beta 1-glycoprotein (SP1) were measured in 21 women after successful in vitro fertilization and embryo transfer. Of the 21 pregnancies, 14, including 1 twin gestation, progressed successfully to term. The remaining seven, composed of tubal (n = 3), anembryonic (n = 1), and spontaneously aborted (n = 3) pregnancies, failed during the first half of pregnancy. Placental protein measurement was of no diagnostic value in the detection of anembryonic pregnancy. Similarly, measurement of hCG and SP1 could not readily distinguish tubal ectopic from normal intrauterine pregnancies. By contrast, the predictive value (38.9%) of a depressed PAPP-A level in conjunction with superior diagnostic sensitivity (70%) and relative risk factor (23.6) proved to be of greater diagnostic value in this potentially lethal condition. In the absence of ultrasonography, the biochemical diagnostic indices were comparable in the prediction of spontaneous abortion. However, in the presence of a live fetus, PAPP-A levels were consistently depressed (sensitivity, 91.7%) many weeks before pregnancy demise. The relative risk factor of depressed PAPP-A levels was 29 times greater than the risk associated with a depressed hCG level. These findings further demonstrate the potential diagnostic value of PAPP-A measurement for monitoring postimplantation embryo viability.

Monitoring of postimplantation embryo viability by measurement of PAPP-A, SP1, and hCG

After successful in vitro fertilization and embryo transfer, chorionic gonadotropin, pregnancy-specific beta 1-glycoprotein, and pregnancy-associated plasma protein-A were measured in serum samples collected serially from 21 patients. While 14 pregnancies, including one twin pregnancy, progressed successfully to term, the remaining seven pregnancies failed during the first half of gestation. This latter group consisted of three tubally implanted, one anembryonic, and three spontaneously aborted pregnancies. Circulating levels of hCG, SP1, and PAPP-A in the patient with an anembryonic pregnancy were within normal limits. Similarly, 90.5% of the serum samples obtained from women with tubal pregnancies showed hCG levels within normal limits. By contrast, only two of these samples had detectable PAPP-A, of which only one was within normal limits. Of the samples obtained from the patients who spontaneously aborted, including one patient with normal ultrasonic findings up to 48 hours prior to the event, 85.7% had PAPP-A concentration below the 10th percentile, whereas only 16.7% of these samples showed depressed hCG levels. These data suggest that PAPP-A measurement has great clinical potential in the management of compromised early pregnancies.