Serum markers for Down's syndrome in women who have had in vitro fertilisation: implications for antenatal screening

To examine the Down's syndrome screening positive rate among in vitro fertilisation (IVF) pregnancies, we measured second trimester serum marker levels in singleton IVF pregnancies (cases) and in five non-IVF pregnancies (controls) matched to each case for gestational age, age of mother, and duration of storage of the serum sample. There were 151 IVF pregnancies in which alpha fetoprotein, unconjugated oestriol (uE3), free beta-human chorionic gonadotrophin (hCG) and total hCG were measured, 104 IVF pregnancies in which free alpha-hCG was measured, and 39 IVF pregnancies in which inhibin A was measured. Median uE3 levels were 6% lower (P = 0.003), median free beta-hCG 9% higher (P = 0.024), and median total hCG 14% higher (P = 0.026) in IVF pregnancies compared with controls. The screen positive rate in the IVF pregnancies (28%) was about twice as high as that in controls (17%). High hCG levels may be explained by progesterone remaining high in IVF pregnancies. The low uE3 levels remain unexplained. In Down's syndrome screening in IVF pregnancies hCG and uE3 values should be adjusted to avoid the high screen positive rate.     

False positive serum biochemical screening and subsequent fetal loss in women less than 35 years of age

Objective To examine the fetal loss rate in women younger than 35 years of age following a false positive serum biochemical screening.
Design Retrospective analysis of case records between 1991 and 1998.
Setting Fetal medicine unit of a large teaching hospital.
Population Four hundred and fifty-six women with singleton pregnancies and false positive serum biochemical screening for Down's Syndrome (study group). Nine hundred and twelve matched controls with true negative serum biochemical screening (control group).
Methods Women of both groups had a second trimester serum screening for Down's Syndrome using alpha fetoprotein, human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE₃); and they also underwent genetic amniocentesis.
Results The overall fetal loss rate in the study group was 5.3% (24/456), compared with 1.65% (15/912) in the control group RR 3.2, 95% CI 1.7-5.99;   P <0.001  ). The majority of fetal losses in the study group occurred after 28 weeks, while in the controls this happened between 24 and 28 weeks of gestation.
Conclusions A false positive serum biochemical screening in women under 35 years of age is associated with a threefold increased risk of subsequent fetal loss. However, most of fetal losses in this group occurred after 28 weeks, indicating that intensive antepartum fetal surveillance could improve the perinatal outcome.     

Screening for Down's syndrome: changes in marker levels and detection rates between first and second trimesters

Objective To monitor changes with gestation in levels of alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (FβhCG) and pregnancy associated plasma protein-A (PAPP-A) in Down's syndrome pregnancies and to compare risks estimated in the first trimester with those obtained by routine screening in the second trimester for the same pregnancies.
Design In each of 47 Down's syndrome pregnancies two maternal serum samples were obtained, one in the first trimester and one in the second trimester. Comparison of marker levels with 10,600 first trimester controls and a smaller sample of second trimester controls allowed case identification criteria based on optimum marker combinations to be developed and compared directly between trimesters.
Setting Biochemical genetics laboratory.
Results FβhCG was an effective marker of Down's syndrome in both the first and second trimesters. PAPP-A levels were significantly reduced in trisomy 21 pregnancies in the first trimester only. Using a population model, these two markers in combination with maternal age gave an overall detection rate of 55% for a 5% false positive rate in the first trimester. For the paired first and second trimester samples, three of six cases classified as low risk by routine second trimester screening were classified as high risk by the first trimester screening protocol of FβhCG/PAPP-A/matemal age. However, fifteen cases identified as high risk by routine second trimester screening were classified as low risk in the first trimester, a net loss in detection of 12 cases by first trimester screening.
Conclusion The data suggest that first trimester detection rates for Down's syndrome using a combination of FβhCG and PAPP-A may vary with gestation and will be lower than those currently obtained by routine second trimester screening with AFP/hCG.     

First trimester screening for Down's syndrome using maternal serum PAPP-A and free β=hCG in combination with fetal nuchal translucency thickness

The aim of this study was to evaluate the potential effectiveness of maternal serum pregnancy-associated plasma protein A (PAPP-A) and free β-hCG in combination with nuchal translucency thickness in first trimester screening for Down's syndrome. Maternal serum levels of PAPP-A and free β-hCG were assayed in stored sera from 32 Down's syndrome and 200 unaffected pregnancies. Fetal nuchal translucency was measured by ultrasound at the time of blood sampling. Screening of Down's syndrome using a combination of maternal age, PAPP-A, free β-hCG and nuchal translucency would achieve a detection rate of 75.8% for a false positive rate of 5%.     

Thromboxane A2 and prostacyclin levels in molar pregnancy

Summary. Plasma levels of thromboxane (TX) A₂ and prostacyclin (PGI₂), as measured by radioimmunoassay of their respective stable metabolites TXB₂ and 6–keto PGF_1α, were studied in six molar pregnancies immediately before, immediately following and 24 h after evacuation of the uterus. The mean (SD) levels for TXB₂ were 150 (41), 137 (32) and 125 (25) pg/ml respectively, and for 6–keto PGF_1α the respective values were 225 (52), 226 (127) and 213 (49) pg/ml. There was no significant difference in the levels of prostanoids between the samples taken at the various time intervals. The concentration of these prostanoids in molar intravesicular fluid was also determined. Their respective mean (SD) pg/ml values were 3682 (760) for TXB₂ and 2969 (744) for 6–keto PGF_1α. In 15 normal pregnancies of equivalent gestation, the mean amniotic fluid levels of TXB₂ and 6–keto PGF_lα were 34 (17) and 146 (86) pg/ml respectively. The ability of molar trophoblast to generate the prostanoids from [¹⁴C]arachidonic acid in vitro was also demonstrated. Mean (SD) values for TXB₂ and 6-keto PGF_1α were 12.2 (2.6) and 13.2 (1.8) pg/mg protein/min, respectively. It is likely that the high concentrations of prostanoids in vesicular fluid reflect the synthesizing ability of the villus vesicles. The mole contributes little to the circulatory prostanoids possibly because its villi are deficient in blood circulation.     

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.     

Serum concentrations of cancer antigen 125, placental alkaline phosphatase, cancer-associated serum antigen and free beta human chorionic gonadotrophin as prognostic markers for epithelial ovarian cancer

Objective To investigate the prognostic significance of elevated levels of cancer antigen 125 (CA125), placental alkaline phosphatase (PLAP), free β human chorionic gonadotrophin (hCG) and cancer-associated serum antigen (CASA) in women with primary epithelial ovarian carcinoma.
Design A two year follow up study of survival.
Setting A tertiary care gynaecological oncology unit.
Participants One hundred and eleven women with histologically confirmed epithelial ovarian cancer.
Main outcome measures Survival over a two year period.
Results Stage corrected log-rank χ² tests demonstrated a significant effect on survival for all four tumour markers (CA125   P = 0.0142  ; PLAP   P < 0.0001  ; CASA   P = 0.0098  ; hCG   P = 0.0002  ). This was confirmed when each variable was fitted together with disease stage in Cox proportional hazard models. When fitted as multiple variables in a Cox proportional hazard model, the addition of free β- hCG and CASA to disease stage, PLAP concentrations and CA125 levels did not demonstrate further prognostic value.
Conclusions Levels of all four markers correlate with survival in patients with epithelial ovarian cancer. The combination of PLAP and CA125 concentrations together with disease stage may be used to predict survival but the addition of hCG and CASA levels do not give additional prognostic information.     

Pre-eclampsia is associated with airway hyperresponsiveness

Several large retrospective cohort studies demonstrate that pre-eclampsia is common in asthmatics. Whether airway hyperresponsiveness (AHR), a hallmark of asthma, is associated with pre-eclampsia is unknown. We measured AHR, using a methacholine challenge, and atopy in 19 women 3–60 months postpartum following pre-eclamptic or normotensive pregnancies. The geometric mean (95% CI) concentration of methacholine required to produce a >20% fall in the forced expiratory volume in 1 second (PC₂₀ FEV₁) was 8.9 (2.2–36) mg/ml in pre-eclamptics versus 72 (32–131) mg/ml in controls ( P = 0.01) and 9 (1.9–40) mg/ml in atopic pre-eclamptics without asthma versus 54 (17–174) mg/ml ( P = 0.038) in matched controls. Therefore, AHR was increased in women who have had pre-eclampsia. This association and its possible mechanisms warrant further investigation.     

Liver function following pregnancy complicated by the HELLP syndrome

Serum levels of aminotransferases, lactate dehydrogenase, gammaglutamyl transferase, alkaline phosphatase, albumin and conjugated bilirubin, measured in 54 women at a median of 31 months (range 3–101) after pregnancies complicated by the HELLP syndrome, were not elevated. Total bilirubin levels, however, were elevated in 20'1/0 of these women; this represents a significant difference from the prevalence in 151 women with a previous normal pregnancy (  χ²= 12.23  ,   P < 0.001  ), or in the normal female population (  χ²= 22.34  ,   P < 0.00001  ). This raises the possibility that a dysfunction of the bilirubin-conjugating mechanism represents a risk factor for the development of the HELLP syndrome.     

Circulating placental proteins (hCG, SP1 and PP5) in trophoblastic disease

Summary. Scrum human chorionic gonadotrophin (hCG), pregnancyspecific β₁-glycoprotein (SP₁) and placental protein 5 (PP5) levels have been measured by radioimmunoassay in 20 patients (116 samples) with hydatidiform mole, one patient (nine samples) with invasive mole and 10 patients (103 samples) with choriocarcinoma. Measurement of both serum SP₁ and hCG are useful in the monitoring of these diseases. The presence of PP5 in hydatidiform mole and its absence in choriocarcinoma support the hypothesis that PP5 is closely associated with the invasive activity of malignant trophoblast.     

Oocyte donation: a review

Summary. Oocyte donation provides an option for achieving pregnancy in women lacking functioning gonads, or in whom IVF techniques have failed to harvest adequate oocytes, or those who do not wish to use their own gametes because of hereditary disease. In agonadal women, artificial menstrual cycles are required before proceeding to gamete donation. A fixed cyclical steroid replacement schedule of oestradiol (E₂) valerate and progesterone (P₄) pessaries was initially used, but the need for synchrony between donor and recipient cycles, and the narrow window for implantation limited the transfer of fresh embryos. Donorrecipient cycle asynchrony can be overcome by using frozen-thawed embryos, or by extending the follicular phase in the recipient to widen the transfer window. Twenty-two pregnancies have now been achieved by the Monash/Epworth group, resulting in the birth of 13 healthy Infants. There were no statistically significant differences in pregnancy rates (per transfer) between transfers in natural cycles (14%, four pregnancies) and steroid replacement cycles (24%, 16 pregnancies). Five pregnancies (36%) were established in women treated with 2 mg of E₂ daily 13–18 days before embryo transfer with P, starting on the day of or the day tollowing oocyte retrieval. E₂ was continued for a median of 85 days (range 49–110) and P₄ for a median of 86 days (range 49–133) after the supposed last menstrual period. All but one delivery was by caesarean section. There were no perinatal deaths and no ectopic pregnancies.     

Plasma prostanoids in pregnancy-induced hypertension

Summary. The concentrations of 13,14-dihydro-15-oxo-prostaglandin F_2α (PGFM), 6-oxo-prostaglandin F1_α,_a (6-oxo-PGF1_α) and thromboxane B₂ (T×B₂) were measured by radioimmunoassay in peripheral plasma from 183 pregnant women attending routine antenatal clinics. A total of 141 patients (47 nulliparous, 94 parous) remained normotensive and had uncomplicated pregnancies. The results from this group showed that there was no significant difference in the concentration of any metabolite in relation to parity or gestational age. The concentrations (pmol/1; means±SD) were PGFM 373±105, 6-oxo-PGF_1α 391±104 and T×B₂ 373±121. Nineteen patients (12 nulliparous, 7 parous) who had pregnancy-induced hypertension (PIH) by the time of sampling (three) or who subsequently developed the symptom (mean time from sampling to diagnosis 11 weeks, range 1–24 weeks) had significantly higher levels of 6-oxo-PGF_lα(574±216; P<0.0005, Student's test) and T×B₂ (603±268; P <0.0005). The concentrations in seven nulliparous patients with PIH and proteinuria were 656±276 for 6-oxo-PGF_3α and 754±228 pmol/1 for T×B₂.     

Cigarette smoking in pregnancy results in marked decrease in maternal hCG and oestradiol levels

Summary. We have examined serum levels of oestradiol (E₂), sexhormone binding globulin (SHBG) and human chorionic gonadotrophin (hCG) during early pregnancy in relation to smoking status at the time of sampling in a series of 147 women. Smoking was associated with significantly depressed serum levels of E₂, SHBG and hCG: in smokers, E₂ levels were on average 17·6% lower ( P =0·037), SHBG levels were 12·4% lower ( P =0·15), and hCG levels were 21·5% lower ( P =0·044). There appeared to be a steady decline in these values with increasing cigarette consumption. These lower hormone levels in smokers may explain certain adverse effects of smoking in pregnancy.     

Velamentous umbilical cord insertion may be suspected from maternal serum α-fetoprotein and hCG

Objective Patients with unexplained elevations in second trimester maternal serum α-fetoprotein or human chorionic gonadotrophin (hCG) concentrations are at increased risk as regards a variety of pregnancy complications and adverse perinatal outcomes. Evidence suggests that elevated α-fetoprotein and hCG concentrations may, in some case, be sensitive indicators of underlying placental pathology, either vascular or inflammatory in nature. The present study was carried out to compare these biochemical markers in pregnancies complicated by velamentous umbilical cord insertion (VCI) with normal pregnancies.
Design An observational study.
Participants Maternal serum hCG and α-fetoprotein concentrations were measured in samples from 76 singleton pregnancies complicated by VCI and from 5200 chromosomally normal controls at 15 weeks of gestation.
Results Maternal serum hCG concentrations were elevated (mean 1·47 multiples of median (MOM)) in affected pregnancies, whereas α-fetoprotein levels were lower (mean 0·88 MOM) in the subjects than in the controls. In relation to Down's syndrome risk assessment, the pattern of the two markers indicated high risk more often in VCI than in pregnancies with normal umbilical insertion. Accordingly, the increased false positive rate (26·3% compared with 6·6%) resulted in a higher rate of invasive techniques for fetal karyotyping in these pregnancies.
Conclusions In obstetric practice, elevated maternal serum hCG concentrations may in some cases be explained as being solely the result of abnormal insertion, which provides a link between unexplained hCG elevation and adverse pregnancy outcome. We suggest colour flow Doppler imaging of cord insertion in pregnancies followed because of unexplained hCG elevation or a false positive result in Down's syndrome screening.     

Determination of the stage of gestation by the assay of chorionic gonadotrophin and Schwangerschaftsprotein 1

Summary. Serial assays of Schwangerschaftsprotein 1 (SP1), SP1_α, SP1_β and human chorionic gonadotrophin were performed in 12 subjects from ovulation until the pregnancies had reached 16 weeks. From these data formulae were devised for deducing the stage of gestation from the concentration of the placental protein. These formulae were then tested by assays on 34 women not included in the original study. Assays of hCG do not give reliable indications of the stage of gestation when this has progressed beyond 9–10 weeks but SP1 assays give predictions of gestation corresponding closely to that derived from the last menstrual period up to 16 weeks gestation.     

Phospholipase activity in the endometrium of women with normal menstrual blood loss and women with proven ovulatory menorrhagia

Summary. The activity of phospholipase A ₂ types 1 and 2 and phospholi-pase C was measured in the endometrium of women with ovulatory menorrhagia and in those with normal menstrual blood loss. In both groups of subjects phospholipase A ₂ type 1 activity was significantly higher in the secretory phase than in the proliferative phase (   P < 0.001  ). The median activity (pmol/mg protein/min) for the proliferative phase was 27–6 in normal subjects and 40–4 in women with ovulatory menorrhagia and for the secretory phase the median activity was 144–5 in normal women and 138–1 in women with ovulatory menorrhagia. There was no difference between the two groups of women at either stage of the cycle. Phospholipase A ₂ type 2 activity was also higher in the secretory phase than in the proliferative phase (   P < 0.05  for normal subjects and   P < 0.001  for women with menorrhagia). The median activity (pmol/mg protein/min) for the proliferative phase was 94–4 (normal subjects) and 56–6 (women with menorrhagia) and for the secretory phase 148–3 (normal subjects) and 142–5 (women with menorrhagia). The activity of phospholipase A ₂ type 2 was significantly lower in the proliferative phase of women with ovulatory menorrhagia compared with normal subjects (   P < 0.05  ). Phospholipase C activity (nmol/mg protein/min) was significantly higher in women with ovulatory menorrhagia (median 8-2) compared with women with normal blood loss (median 5–5) (   P < 0.01  ).     

A case-control study of the effects of birth by caesarean section on intrapartum and neonatal mortality among twins weighing 1500–2499 g

Summary. . The aim of this nationally-based, matched case-control study was to assess the impact of birth by caesarean section on intrapartum, and neonatal mortality among twins weighing 1500–2499 g, born in Sweden between 1973 and 1983. By using data held at the National Medical Birth Registry, Stockholm, 91 such pregnancies (study cases) where one or both twins died were identified. For each case, two controls (in all 182 pregnancies) were allotted at random from the rest of the twin pregnancies, with similar birthweight (±100 g) and year of delivery (±1 year). The number of twins that died was reduced from 73 during the first four years to 22 between 1977 and 1980, and to 6 during the last 3 years of the study period. Almost a quarter (23.1%) had a lethal malformation. The caesarean section rate increased during the study period, but did not differ between cases and controls (  χ²= 1.0  ;   P >0.05  ). The analysis could not confirm a significant difference between cases and controls regarding the number of infants born vaginally in non-vertex presentation (  χ²= 0.1  ;   P >0.05  ). The results of this study appear to indicate that birth by caesarean section was not a major factor related to the improved fetal outcome.     

Reduced fetal exposure to aspirin using a novel controlled-release preparation in normotensive and hypertensive pregnancies

Objectives To examine the fetal effects of a novel controlled-release, low dose aspirin preparation in normal and hypertensive pregnancies.
Design Random double-blind study. Participants assigned to receive conventional formulation aspirin (75 mg), controlled-release low dose aspirin (75 mg), or matching placebo.
Setting National Maternity Hospital, Dublin.
Participants Eighteen women with an uncomplicated pregnancy and 18 women with preeclampsia.
Main outcome measures Urine was analysed for metabolites of thromboxane and prostacyclin by gas chromatography, mass spectrometry. Serum thromboxane B₂, was determined in maternal and cord blood.
Results Both aspirin preparations reduced maternal serum thromboxane B₂, by 95% and induced similar reductions in the urinary 11-dehydro-thromboxane B₂, a major metabolite of thromboxane A₂ in vivo. In contrast, neither preparation altered urinary 2,3–dinor-6-keto PGF_1α, the major metabolite of prostacyclin. Despite their similar effects in the mothers, the two aspirin preparations differed in their effects on the fetus. While both suppressed cord fetal thromboxane B₂, this was significantly (  P < 0.005  ) less for the controlled-release preparation (210 ± 42 ng/ml for placebo vs 109 ± 22 ng/ml for controlled-release aspirin and 44 ± 9 ng/ml for regular oral aspirin).
Conclusions At equivalent maternal suppression of serum thromboxane B₂, a controlled aspirin release preparation results in lower fetal exposure than regular oral aspirin.     

Integrin expression in cervical carcinoma

Heatley MK, Corke K. Integrin expression in cervical carcinoma. Int J Gynecol Cancer 1998; 8: 203–206.
Integrin expression was studied in a series of 36 cervical carcinomas using antibodies to integrins αvβ₅, α₃, β₁ and β₄. Integrins αvβ₅, α₃ and β₁ were localized to the cell membrane in well differentiated (0/13, 2/4 and 4/14 cases) and moderately differentiated adenocarcinomas (0/6, 1/5 and 1/6 cases, respectively) and in adenosquamous (2/6, 2/5 and 3/6) well differentiated (1/4, 0/3, and 3/5) and moderately differentiated (1/2, 1/3 and 1/3) squamous cell carcinomas. Two antibodies (AA3 and 439-B) located integrin β₄ to the cell membranes and cytoplasm of well (13/13 and 10/12 cases) and moderately differentiated (6/7 and 5/6 cases) adenocarcinomas, cases of adenosquamous carcinoma (6/6 and 5/6 cases), and well (4/4 and 3/4 cases) and moderately (3/3 and 3/4 cases) differentiated squamous cell carcinomas. In conclusion, integrin expression was identified most frequently with the antibodies to β₄ which was localized to cervical carcinomas of varying grades and histological types. Immuno-staining was identified less frequently with the antibodies to αvβ₅, α₃ and β₁.     

Maternal serum free β-hCG at 10 to 14 weeks of gestation in trisomic twin pregnancies

Maternal serum free β-hCG was measured at 10 to 14 weeks of gestation in 136 normal twin pregnancies and in 12 twin pregnancies where one or both fetuses had trisomy 21. The values were compared with a normal range from 4181 singleton pregnancies. In the normal twins the median free β-hCG (65 ng/mL) was about twice as high as in singletons (34 ng/mL z =−12.1,   P < 0.0001  ). In the trisomy 21 group the median free β-hCG (95 ng/mL) was significantly higher than in normal twins ( z = 2.1,   P < 0.05  ). However, only one of the trisomic pregnancies had a level above the 95th centile. In twin pregnancies maternal serum free β-hCG at 10 to 14 weeks of gestation is unlikely to be useful in the prediction of fetal trisomy 21.