Fetal lactic dehydrogenase variation in normal pregnancy and in cases of severe intra-uterine growth restriction

Physiological and pathological fetal levels of lactic dehydrogenase (LDH), including its five different iso-enzymes are still poorly known. Our objectives were to compare total LDH levels and its five iso-enzymes between a control group of healthy fetuses and a group of fetuses with severe intra-uterine growth restriction (IUGR), and to determine the biochemical associations and the prognostic value of elevated LDH activity in fetuses with IUGR. Total LDH levels, haematologic values and liver enzyme activities were measured in 108 healthy fetuses from 17 to 37 weeks of gestation and in 44 fetuses with severe IUGR. Total fetal LDH in plasma from the healthy fetuses were constant throughout pregnancy (mean (SD)= 305.09 (46.97)). Total LDH values in plasma significantly increased in cases of IUGR (p=0.003), and the degree of increase was significantly correlated with fetal erythroblastosis (n =44, r=0.80, p<0.001). LDH 5 significantly decreased in the IUGR group (p=0.03). Total LDH values strictly above 400 IU/l (a value equal to the mean+2 SD in the healthy fetus group) were found to be significantly associated with thrombocytopenia (p<0.001), erythroblastosis (p=0.008) and an increase in AST value (p=0.03). These results suggest that the fetal LDH value in plasma is a useful biological marker for severe chronic distress.     

Fetal serum concentrations of cystatin C and beta2-microglobulin as predictors of postnatal kidney function

OBJECTIVES: Cystatin C and beta(2)-microglobulin are established serum markers of renal function in children and adults. In contrast to creatinine, diaplacental exchange is minimal. The aim of the study was to establish reference values in fetal serum and to test their efficiency in predicting postnatal kidney function. STUDY DESIGN: This was a prospective noninterventional study measuring cystatin C and beta(2)-microglobulin by particle-enhanced immunoturbidimetry in excess serum from 129 cordocenteses performed in 84 fetuses. Reference intervals (mean +/- 1.96 SD) were calculated in a subgroup of 54 fetuses without evidence of kidney disease, and these reference values were evaluated in 75 sera from 55 fetuses. RESULTS: Mean cystatin C was 1.66 +/- 0.202 mg/L (upper limit 2.06), and mean beta(2)-microglobulin was 4.25 +/- 0.734 mg/L. Unlike cystatin C, beta(2)-microglobulin decreased significantly with gestational age so that the upper reference limit was 7.19-0.052 x gestational age in weeks. beta(2)-Microglobulin had higher sensitivity (90.0% vs 63.6%) and cystatin C a higher specificity (91.8% vs. 85.5%) for the prediction of impaired renal function; diagnostic efficiency was equal (87.6% vs. 86.1%). Fetuses with impaired renal function at birth or who were aborted for renal malformations had higher cystatin C concentrations than those in a control group. beta(2)-Microglobulin was increased only in fetuses who were aborted. CONCLUSION: Fetal serum cystatin C and beta(2)-microglobulin concentrations may be useful predictors of postnatal kidney function.     

MRI with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) assessment in the evaluation of normal and abnormal fetal kidneys: preliminary experience

OBJECTIVE: To investigate apparent diffusion coefficient (ADC) mapping with the measurement of renal tissue ADC value of normal and pathological fetal kidneys at various gestational ages (GAs). METHODS: Fifty pregnant women underwent magnetic resonance images (MRI) after ultrasound (US) for suspected fetal genitourinary disorders (16) or for suspected disorders in other organs (34). A multiplanar study of urinary system was obtained by using conventional T2-weighted sequences and echo planar imaging (EPI); Diffusion-weighted images and ADC maps were evaluated. The renal tissue ADC value was measured for all normal and abnormal fetuses and related to GA. RESULTS: MRI confirmed urinary anomalies in 15 fetuses [2 renal developmental variants, 2 nephropathies, 4 multicystic dysplastic kidneys (MCDK), 7 renal tract dilatations] and detected normal kidneys in the remaining 35 fetuses. Normal renal parenchyma showed bright signal on diffusion-weighted images with ADC values ranging from 1,065 to 1,327 microm(2)/s with a tendency to decrease over GA. A pathological ADC was detected in cases of bilateral MCDK, huge dilatations and in cases of nephropathies. CONCLUSION: Diffusion-weighted imaging (DWI) with ADC mapping can be used in the evaluation of fetal renal parenchyma and may become a tool of assessing function of the fetal kidney by means of measurement of renal tissue ADC values.     

Correction of fetal anemia on the middle cerebral artery peak systolic velocity

OBJECTIVE: To assess the effect of correction of fetal anemia on the middle cerebral artery peak systolic velocity values. METHODS: With Doppler ultrasonography, middle cerebral artery peak systolic velocity was measured in 41 fetuses before and immediately after 54 intrauterine transfusions for severe red blood cell alloimmunization. The fetuses were divided into two groups: 17 fetuses studied at first transfusion (group A), and 24 fetuses enrolled to the study after the first transfusion (group B). Both fetal hemoglobin and middle cerebral artery peak systolic velocity were plotted over the respective reference ranges as a function of gestational age. Both values were expressed as multiples of the median and analyzed with paired t test. RESULTS: The values of middle cerebral artery peak systolic velocity decreased in all but one fetus of group B (P <.05). The values of middle cerebral artery peak systolic velocity before transfusion were above the upper limit of the reference range in 60% of the fetuses of group A and in 38% of group B, respectively. After correction of anemia, only one value remained above the upper limit of the reference range. CONCLUSION: The correction of fetal anemia with intrauterine blood transfusion decreases significantly and normalizes the value of the fetal middle cerebral artery peak systolic velocity.     

Fetal serum ss2-microglobulin and cystatin C in the prediction of post-natal renal function in bilateral hypoplasia and hyperechogenic enlarged kidneys

OBJECTIVES: To evaluate fetal serum ss2-microglobulin and cystatin C in the prediction of post-natal renal function in bilateral hypoplasia and hyperechogenic enlarged kidneys. Predicting post-natal renal function is crucial to the prenatal evaluation of fetal nephropathies. Prenatal ultrasound can identify terminal renal failure, but is not sensitive enough to identify infants whose post-natal renal function will be impaired. Fetal serum ss2-microglobulin and cystatin C are potential predictors of post-natal renal function. METHODS: Fifty-four prenatally diagnosed cases of bilateral nephropathy were retrospectively reviewed. Final diagnosis was established using histological or post-natal findings: renal hypoplasia (n = 7), cystic dysplasia (n = 9), autosomal dominant polycystic kidney disease (ADPKD; n = 8) or autosomal recessive polycystic kidney disease (ARPKD; n = 22) and transient sonographic abnormalities (n = 8). Fetal serum ss2-microglobulin and cystatin C were assayed respectively in 54 and 38 cases. The prognostic value of these markers was assessed in terms of the post-natal outcome. RESULTS: In bilateral kidney hypoplasia and cystic dysplasia, ss2-microglobulin and cystatin C were significantly (p < 0.0001 and p < 0.02 respectively) higher than in the normal control group. In hyperechogenic fetal kidneys (ARPKD, ADPKD and transient sonographic abnormalities), these markers were not different from controls. However, whereas normal values cannot exclude renal failure, abnormal values predict post-natal renal failure. CONCLUSIONS: In bilateral renal hypoplasia and dysplasia, fetal serum ss2-microglobulin and cystatin C are good markers for post-natal renal function. However, in bilateral renal hyperechogenic enlargement, abnormal values are associated with poor post-natal renal function, but normal values cannot preclude renal failure.     

Fetal morbidity and mortality after acute human parvovirus B19 infection in pregnancy: prospective evaluation of 1018 cases

OBJECTIVE: To determine more precisely the incidence of fetal complications following maternal parvovirus B19 infection at various gestational ages. METHODS: An observational prospective study of 1018 pregnant women whose acute B19 infection was serologically confirmed in our laboratory. RESULTS: The observed rate of fetal death throughout pregnancy was 6.3% (64/1018) (95% confidence interval [CI]: 4.9, 8.0). The fetal death rate for those infected within the first 20 weeks of gestation (WG) was 64/579 (11.0%). Fetal death was only observed when maternal B19 infection occurred before the completed 20 WG. The observed stillbirth proportion was 0.6% (6/960). Three of six stillbirth cases presented with fetal hydrops. The overall risk of hydrops fetalis was 3.9% (40/1018) (95% CI: 2.8, 5.3). Three of 17 cases with non-severe hydrops and 13 of 23 cases with severe hydrops received intrauterine transfusion(s). The proportion of fetuses with severe hydrops that survived following fetal transfusions was 11/13 (84.6%). All of the non-transfused fetuses with severe hydrops died. CONCLUSION: Our data demonstrate a relevant B19-associated risk of fetal death, which is largely confined to maternal B19 infection in the first 20 WG. Timely intrauterine transfusion of fetuses with severe hydrops fetalis reduces the risk of fetal death. Parvovirus B19-associated stillbirth without hydropic presentation is not a common finding.     

Maternal serum concentrations of CA-125 in second trimester pregnancy complicated by congenital fetal anomalies

OBJECTIVE: The purpose of the study was to determine the value of maternal serum CA-125 concentrations in pregnancies complicated by fetal anomalies with or without hydramnios. STUDY DESIGN: The study population (n=40) consisted of the following four groups of patients: (1) 10 women with abnormal maternal serum alpha fetal protein (MSAFP) in whom no fetal anomalies were observed; (2) 10 women in whom fetal anomalies were diagnosed in addition to abnormal MSAFP; (3) 10 women with fetal anomalies accompanied by hydramnios and abnormal MSAF, and (4) 10 women had normal MSAFP and were diagnosed with hydramnios without fetal anomaly. The control group consisted of 10 patients who were matched for gestational age with normal MSAFP and normal ultrasonographic examination. In all 50 cases MSAFP and maternal serum CA-125 levels were assessed. CA-125 was measured using OC 125 monoclonal antibody (IMX CA-125, Abott Lab. IL) and a value of >20 U/ml was defined as abnormal. RESULTS: Maternal serum CA-125 levels were significantly higher in the study group than in the control group, 19.8+/-15.9 U/ml and 9.9+/-4.0 U/ml (P=0.015). The difference was even greater when patients with malformed fetuses and hydramnios were compared to those with fetal anomalies and normal amount of amniotic fluid, 32.4+/-12.7 U/ml and 7.2+/-2.1 U/ml, respectively (P=0.0005). The maternal serum CA-125 levels in patients with hydramnios but without fetal anomalies were significantly lower when compared with those of the malformed fetuses and hydramnios, 9.8+/-2.3 U/ml and 32.4+/-12.7 U/ml, respectively (P=0.002). CONCLUSION: Maternal serum CA-125 is lacking in value for screening fetal structural anomalies as a significant increase in maternal serum CA-125 levels was found only in patients with fetal anomalies accompanied by hydramnios.     

Is there a correlation between maternal serum TGF-β1 levels and fetal hydronephrosis?

Objective: We aimed to identify a noninvasive marker for clinically significant fetal uropathies. To achieve this aim, we detected TGF (transforming growth factor)-β1 serum level which rises in neonatal hydronephrosis, in pregnant patients with fetal hydronephrosis.

Materials and methods: We evaluated 44 patients, all of whom were pregnant and had a gestational age between 20 and 30 weeks. Twenty-two patients had normal maternal renal ultrasound imaging and had a fetus with fetal hydronephrosis (Group A). The remaining twenty-two patients had normal maternal and fetal renal ultrasound imaging (Group B). The maternal serum levels of TGF-β1 were measured with a sandwich enzyme-linked immunosorbent assay (ELISA) using a commercially available kit.

Results: The median value for the study group was 55.90?pg/mL (9.67?±?574.45) and for the control group was 59.49?pg/mL (12.49?±?402.04). There was no statistical difference in serum TGF-β1 levels between the groups (p?=?0.769 – Mann–Whitney U test). In the study group, the diameter of the right renal pelvis was 5.7?mm (5.1–8.9?mm), while the diameter of left renal pelvis was 5.75?mm (5.3–10.04?mm).

Conclusion: In our study, the circulating TGF-β1 levels were not statistically different in the fetal hydronephrosis group when compared to the controls. According to our study, TGF-β1 is not useful in the detection and follow-up of fetal hydronephrosis. We therefore require further studies involving larger groups with moderate or severe fetal hydronephrosis to detect the usefulness of the serum levels of TGF-β1 in pregnant women with fetal hydronephrosis.     

Fetal serum alpha-fetoprotein in alloimmunised pregnancies

OBJECTIVES: Maternal serum alpha-fetoprotein (AFP) levels have been known to be increased in red blood cell alloimmunisation. Since AFP is now thought be a pro-erythropoietic factor, we wished to evaluate fetal serum levels of AFP in cases of alloimmunised pregnancies. METHODS: We studied AFP levels in 32 fetal serum samples from women with red blood cell alloimmunisation at the time of the first fetal blood sampling. We expressed the levels of AFP and haemoglobin as absolute numbers and as delta values (number of SDs by which the observed value differed from the normal mean for the same gestation). Main outcome measures were fetal serum AFP levels and fetal haemoglobin concentration. RESULTS: Overall, fetal AFP level was higher than normal in the cases (delta values 2.4 +/- 5.5 SD). However, mildly affected non-hydropic cases had higher levels than severely affected fetuses with hydrops. CONCLUSIONS: Fetuses affected by red blood cell alloimmunisation have increased levels of serum AFP but these levels fall back to low levels in severe anaemia especially with hydrops, which could represent the failing of a compensatory erythropoietic mechanism. Our results suggest that fetal haematopoiesis is activated early in red blood cell alloimmunisation but was subsequently impaired.     

Fetal growth and fetal glucose and C-peptide levels in relation to the degree of anemia in fetuses affected by rhesus iso-immunization

Fetal growth rate was determined by measuring the fetal biparietal diameter at 63 two-week time points during the second trimester in 14 patients with severe Rhesus isoimmunization. Growth rate was found to be related to the fetal hemoglobin concentration which was determined at the end of each 2-week period. Fetuses with a hemoglobin concentration of less than 30% of the normal value had a significantly decreased growth rate (p less than 0.01). These fetuses had also reduced C-peptide (p less than 0.05) and increased glucose levels (p less than 0.1) compared with less anemic fetuses. The physiological background to impaired fetal growth in cases of severe fetal anamia at Rhesus iso-immunization is discussed.     

Fetal sex dependent hormone levels in early pregnant women with elevated maternal serum alpha-fetoprotein

Maternal serum and amniotic hormone levels have been investigated in two groups of women in pregnancy weeks 18-21. One group (B) was composed of women with high alpha-fetoprotein levels in serum without fetal abnormality, and a matched control group (A) with normal alpha-fetoprotein levels in serum. Amongst group B women were four pregnancy complications: two spontaneous abortions, one premature delivery, and one cesarean section due to fetal asphyxia. Group B women were significantly different from group A women. Thus, higher maternal serum levels of total estriol (P = 0.030), testosterone (P = 0.016), and alpha-fetoprotein (P = 0.018) were noted in the presence of male fetuses; and higher hPL (P = 0.004), FSH (P = 0.037), and alpha-fetoprotein (P = 0.002) concentrations in women carrying female fetuses, who were accompanied by lower total estriol concentrations (P = 0.045). Differences between groups B and A in terms of amniotic fluid analyses were only related to female fetal sex. Thus, group B showed higher hPL (P = 0.028), testosterone (P = 0.020), and FSH (P = 0.006) levels, and lower alpha-fetoprotein (P = 0.013) concentrations. It is concluded that elevated maternal serum levels of alpha-fetoprotein are accompanied in female fetuses by an endocrine milieu different from that of matched controls. This difference may put the conceptus at a disadvantage, but the majority of the girls were born on time without signs of small-for-date.     

Diagnosis of fetal parvovirus B19 infection: value of virological assays in fetal specimens

Objective  The purpose of our work was to examine the most reliable laboratory diagnosis of fetal parvovirus B19 infection in hydropic fetuses by evaluating the most appropriate clinical sample and laboratory test.
Design  B19 DNA detection in fetal samples and serological signs of B19 infection in the respective mothers. Samples collected between January 2000 and July 2008.
Setting  Microbiology, University of Bologna, Bologna, Italy.
Samples One hundred thirty-five fetal samples (58 fetal cord blood and 77 amniotic fluid samples) and 109 serum samples collected from 109 pregnant women.
Methods  Validated and certified in situ hybridisation assay (ISH) and polymerase chain reaction–enzyme-linked immunosorbent assay (PCR-ELISA) were performed on fetal samples to detect B19 DNA. B19-specific antibodies were investigated in maternal serum samples by a commercial enzyme immunoassay.
Main outcome measures  Parvovirus B19 DNA detection in fetal specimens was analysed in relation to maternal serological signs of infection.
Results  Parvovirus B19 DNA was detected in 22.41% of fetal cord blood and 36.36% of amniotic fluid samples. A statistically significant difference was found between DNA detection by ISH (23.70%) and PCR-ELISA (14.81%) ( P = 0.004). Only 11.76% of fetuses with virological diagnosis of B19 infection were from women with serological signs of acute/recent B19 infection.
Conclusions  Diagnosis of fetal parvovirus B19 infection cannot always rely on maternal serological investigations but rather on the virological analysis of fetal samples. Both fetal cord blood and amniotic fluid samples are suitable for diagnosis, but the detection of B19 DNA in the cells of amniotic fluid samples by ISH proved to be the most reliable diagnostic system.     

Fetal obstructive uropathy: is urine sampling useful for prenatal counselling?

OBJECTIVES: To evaluate whether fetal urinary sodium and chloride provide clinically useful information in addition to ultrasound in bilateral obstructive uropathy. METHODS: Sonographic features and urinary concentrations of sodium and chloride were evaluated in fetuses with bilateral obstructive uropathy. After a minimum of 12 months of postnatal follow-up, cases that developed increased serum creatinine (greater than 50 micromol/L) were compared with those that did not. RESULTS: Of the cases studied, 16/35 died perinatally, all showing anamnios and markedly elevated urinary electrolytes. Of the survivors, ten maintained normal postnatal serum creatinine, whereas nine did not. The frequency of reduced amniotic fluid/olygohydramnios was higher in cases that developed increased serum creatinine (four out of nine) than in those that did not (nil). Sodium above the 95th percentile was 100% specific and 44% sensitive to predict an increased serum creatinine during early infancy, while chloride above the 95th percentile was 70% specific and 56% sensitive. All seven cases in which urinary sodium was elevated and/or amniotic fluid volume was reduced developed renal failure. CONCLUSION: Urine sampling slightly improved renal function prediction, but this must be balanced against its fetal risks.     

A cardiovascular profile score in the surveillance of fetal hydrops

Objective.?To assess the value of a cardiovascular profile score in the surveillance of fetal hydrops.

Methods.?In a retrospective study, 102 hydropic fetuses were examined between 15 and 37 completed weeks of gestation with ultrasonographic assessment of hydrops, heart size, and cardiac function, and arterial umbilical and venous Doppler sonography of the ductus venosus (DV) and the umbilical vein (UV). A cardiovascular profile score (CVPS) was constructed by attributing 2 points for normal and taking away 1 or 2 points for abnormal findings in each category. The score of the final examination prior to treatment, delivery, or fetal demise was compared to the fetal outcome in these 102 fetuses after exclusion of terminated pregnancies. The scores of the first and last examinations were compared in 40 fetuses and the relationship between these scores and the evolution of fetal hydrops and fetal outcome was assessed.

Results.?Twenty-one pregnancies were terminated (21%). Fifty-four of the remaining 81 hydropic fetuses survived (67%) and perinatal death (PNM) occurred in 27 fetuses (33%). The median CVPS was 6.0 (IQR 4.75–8.00) for all fetuses, with a median of 6.0 (IQR 5.00–6.00) in fetuses who died in the perinatal period compared to a median of 7.0 (IQR 4.00–8.00) in those who survived (p < 0.035). All fetuses in this study had a ‘severe’ form of hydrops with skin edema. The best predictor for adverse outcome was the venous Doppler sonography of UV and DV, in particular umbilical venous pulsations. Among fetuses included in the longitudinal arm of the study, the survival rate was 40% and the PNM was 60%, after exclusion of terminated pregnancies. CVPS increased by a median of 1 (IQR 0.00–2.00) point in the last exam for those fetuses that lived, whereas among those fetuses that died, the CVPS decreased by a median 1.5 (IQR 0.25–2.75) points (p < 0.001).

Conclusions.?The fetal cardiovascular profile score can be used in the surveillance of hydropic fetuses for prediction of the presence of congestive heart failure and as an aid for predicting fetal outcome.     

Fetal intervention in obstructive uropathy: prognostic indicators and efficacy of intervention

Management of the fetus with bilateral hydronephrosis is controversial; ability to predict outcome and efficacy of prenatal intervention are unknown. We studied 40 fetuses referred for ultrasonography, examination of fetal urine, and possible therapy. We retrospectively assigned fetuses to a good prognosis group if fetal urine was hypotonic (sodium less than 100 mEq/L, chloride less than 90 mEq/L, osmolarity less than 210 mOsm/L) and there was no ultrasonographic evidence of dysplasia; we assigned fetuses to a poor prognosis group if even one criterion was abnormal. Survival was greater in the good prognosis group than in the poor prognosis group (81% vs 12.5%; 87% vs 30%, excluding abortions) (p less than 0.005). We then attempted to assess the efficacy of prenatal urinary decompression by comparing outcome within the good and poor prognosis groups. Survival with intervention was greater in both the good prognosis group and the poor prognosis group (89% vs 70% and 30% vs 0%). In 6 of the 8 survivors in the good prognosis group, severe oligohydramnios was reversed by decompression. We conclude the fetal urine electrolyte levels and ultrasonographic appear helpful in predicting residual fetal renal function and neonatal outcome and that prenatal decompression may prevent the development of fatal pulmonary hypoplasia.     

Prenatal diagnosis of the hemodynamics of fetal renal disease by color Doppler ultrasound

OBJECTIVE: Hemodynamic analysis of the fetal renal artery elucidated the function of the renal glomerulus and renal tubule in normal growth fetus and was weighed against fetal renal disease. DESIGN: The subjects were fetuses from pregnant women who gave informed consent. There were 6 cases of polycystic kidney, 4 cases of hydronephrosis and 33 cases of fetuses presenting with normal growth. A longitudinal study was performed for normal growth fetuses. Using maximum systolic velocity (V(max)), pulsatility index (PI) and resistance index (RI), the blood flow was measured initially at 20-24 weeks of pregnancy and every 4 weeks thereafter. The measurement was performed 5 times in total. Also, for fetal renal disease, the measurement was performed using the same indexes. RESULTS: In 2 cases of polycystic kidney, which led to death due to postpartum afunctional kidney, V(max) indicated the lower level of less than mean -1.5 SD. In 1 case of single hydronephrosis, the single afunctional kidney was observed postpartum due to blood flow disruption. In 7 cases of normal renal function after birth, it indicated the lower level in some gestational ages but was generally in the normal range. CONCLUSIONS: Using indexes to evaluate the glomerulus and renal tubule of fetal renal disease, mean -1.5 SD of V(max) can be considered to be the lower limit in the normal range and expected to be an important factor for the final outcome.     

The nonpredictive value of fetal urinary electrolytes: preliminary report of outcomes and correlations with pathologic diagnosis

Fetal urine was sampled 12 times in nine fetuses with sonographically diagnosed urinary tract obstruction to assess renal function. By previously proposed criteria, four fetuses were predicted to have poor renal function. Two of these fetuses were found to have renal dysplasia on autopsy after elective termination. The other two died in the neonatal period but only one of these had histologic evidence of renal dysplasia. Five fetuses were predicted to have good renal function. Three of these developed renal failure after birth, one was found to have renal dysplasia on autopsy after elective termination, and one is alive and well. We conclude that fetal urine electrolytes are not necessarily an accurate predictor of neonatal renal function.     

Thyroid hormone regulates renocortical COX-2 and PGE2 expression in the late gestation fetal sheep

Cyclooxygenase 2 (COX-2) is important for development of the fetal kidney. Precisely how renal COX-2 expression is regulated in fetal life is unclear. The hypothesis that thyroid hormone positively regulates COX-2 and PGE(2) levels in the late gestation fetal kidney cortex was tested. Sham, thyroidectomized (TX), and TX + thyroid hormone replacement (R) fetal sheep were studied. TX was performed at 120 days gestational age (dGA). TX + R fetuses were continuously infused with thyroxine from 3 days after surgery until study completion. Fetal kidney cortex was obtained at 137 dGA for measurement of renal cyclooxygenase type-2 (COX-2) protein and PGE(2) metabolites. Renocortical COX-2 and PGE(2) levels were significantly lower in TX compared with sham and TX + R fetuses. There were no differences between sham and TX + R fetuses. These findings demonstrate that thyroid hormone positively regulates renal COX-2 and PGE(2) expression in the late gestation fetal sheep kidney.     

Serum prolactin concentration in normal and small for gestational age fetuses.

OBJECTIVES: To study fetal and maternal serum prolactin concentrations in appropriately-grown (AGA) fetuses and in small for gestational age (SGA) fetuses. DESIGN: A cross-sectional study of 27 AGA and 27 SGA fetuses undergoing cordocentesis for prenatal diagnosis or for determination of fetal karyotype and acid-base balance. Serum prolactin concentration was measured by radioimmunoassay. SETTING: Harris Birthright Research Centre for Fetal Medicine. RESULTS: In the AGA group, both fetal and maternal serum prolactin concentration increased significantly with gestation (P < 0.001 and P < 0.01, respectively). In the SGA group, the fetal concentration of prolactin was significantly higher (P < 0.05), but the maternal serum prolactin concentration was not different from that of the AGA group. CONCLUSIONS: The finding of prolactin in the fetal circulation suggests that the anterior lobe of the pituitary is functioning from at least 12 weeks gestation. The increased serum prolactin concentration in SGA fetuses may be the consequence of hypoglycemic stress on the pituitary or the relative immaturity of the inhibitory hypothalamic-pituitary pathways.