Douglas W. Hershey

The incidence of pregnancy-induced hypertension is increased among Colorado residents at high altitude.

Both pregnancy-induced hypertension and high-altitude residence are associated with fetal growth retardation, thereby leading us to hypothesize that pregnancy-induced hypertension would be more common at high than at low altitude. Retrospectively collected data in Colorado revealed that pregnancy-induced hypertension was more common at 3,100 m (12%) than at 2,410 m (4%) or 1,600 m (3%) (P less than 0.001). Proteinuria and edema in the upper extremities were also more frequent at 3,100 m than at 1,600 m (proteinuria = 28% versus 9%, P less than 0.001; edema of upper extremities = 22% versus 13%, P less than 0.01). Blood pressure during pregnancy increased with altitude among all women and those without pregnancy-induced hypertension (analysis of variance, P less than 0.05). In a prospective study at 3,100 m, women with pregnancy-induced hypertension had no change in blood pressure during pregnancy prior to the onset of hypertension (analysis of variance, P = NS), whereas blood pressure decreased in the normal women (analysis of variance, P less than 0.05). Arterial oxygen saturation during the third trimester was inversely related to the degree of hypertension in women with pregnancy-induced hypertension at 3,100 m (r = 0.8, P less than 0.05), thus suggesting that maternal hypoxia may play a previously unsuspected role in the etiology of pregnancy-induced hypertension.

Common trisomy mosaicism diagnosed in amniocytes involving chromosomes 13, 18, 20 and 21: karyotype–phenotype correlations

Karyotype–phenotype correlations of common trisomy mosaicism prenatally diagnosed via amniocentesis was reviewed in 305 new cases from a collaboration of North American cytogenetic laboratories. Abnormal outcome was noted in 10/25 (40%) cases of 47,+13/46, 17/31 (54%) cases of 47,+18/46, 10/152 (6.5%) cases of 47,+20/46, and in 49/97 (50%) cases of 47,+21/46 mosaicism. Risk of abnormal outcome in pregnancies with less than 50% trisomic cells and greater than 50% trisomic cells were: 26% (4/15) versus 60% (6/10) for 47,+13/46, 52% (11/21) versus 75% (6/8) for 47,+18/46, 4.5% (6/132) versus 20% (4/20) 47,+20/46, and 45% (27/60) versus 59% (22/37) for 47,+21/46. Phenotypically normal liveborns were observed with mean trisomic cell lines of 9.3% for 47,+13/46, 8.6% for 47,+18/46, 27% for 47,+20/46, and 17% for 47,+21/46. Cytogenetic confirmation rates were 46% (6/13 cases) for 47,+13/46 mosaicism, 66% (8/12 cases) for 47,+18/46, 10% (10/97 cases) for 47,+20/46, and 44% (24/54 cases) for 47,+21/46. There were higher confirmation rates in pregnancies with abnormal versus normal outcome: 50% versus 44% for 47,+13/46 mosaicism, 100% versus 33% for 47,+18/46, 66% versus 7% for 47,+20/46, and 55% versus 40% for 47,+21/46. Repeat amniocentesis is not helpful in predicting clinical outcome. It may be considered when there is insufficient number of cells or cultures to establish a diagnosis. Fetal blood sampling may have a role in mosaic trisomy 13, 18, and 21 as the risk for abnormal outcome increases with positive confirmation: 1/5 (20%) normal cases versus 5/8 (62%) abnormal cases. High resolution ultrasound examination(s) is recommended for clinical correlation and to facilitate genetic counselling. Copyright

Late first-trimester placental disruption and subsequent gestational hypertension/preeclampsia.

OBJECTIVE: To evaluate the potential relationship between placental disruption in weeks 13 and 14 and the subsequent development of gestational hypertension or preeclampsia. METHODS: Using subjects recruited during a randomized trial funded by the National Institute of Child Health and Human Development, which compared early amniocentesis and late transabdominal chorionic villus sampling (CVS) in weeks 13 and 14, rates of gestational hypertension and preeclampsia were compared between cases with varying degrees of placental disruption. RESULTS: A total of 3,698 of 3,775 randomized subjects had cytogenetically normal pregnancies and were analyzed. A significantly higher rate of hypertension/preeclampsia was observed in the late CVS group (5.4%, n = 1,878) compared with the early amniocentesis cohort (3.5%, n = 1,820; P = .005). This difference persisted after controlling for maternal age, body mass index, parity, previous preterm delivery, smoking, and fetal gender. Early amniocentesis cases were further stratified on the basis of whether the placenta had been penetrated (n = 460) or not (n = 1,360). Risk of hypertensive complications was lowest if the placenta was not traversed (3.4%), greater with placental penetration (3.9%), and highest when the placenta was directly sampled during CVS (5.4%, P = .02). CONCLUSION: We hypothesize that focal disruption of the placenta at 13–14 weeks may increase the risk of hypertension/preeclampsia. These findings provide support for the theory that disturbances in early placentation lead subsequently to maternal hypertension. LEVEL OF EVIDENCE: II-1

Maternal serum α-fetoprotein screening of fetal trisomies

Abstract Thirty-two trisomy pregnancies were retrospectively studied in which the maternal serum level of α-fetoprotein was determined prior to amniocentesis. Median levels of α-fetoprotein in serum (0.83 multiples of the median) and in amniotic fluid (0.72 multiples of the median) were lowered, but this was statistically significant only in the case of amniotic fluid.

Testing for Zika in asymptomatic travelers at risk

2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 B particularly microcephaly, have rapidly come to worldwide attention of health organizations and the general public. Many pregnant patients with increased risk of a serious birth defect elect pregnancy termination. Although the incidence of microcephaly and other fetal anomalies in pregnant Zikainfected women is not yet known, those women with good evidence of Zika infection might elect pregnancy termination, particularly if it is detected early in the pregnancy. Much of the focus on the assessment of pregnant women at risk for vertical transmission of Zika has been with ultrasound diagnosis of microcephaly. However, the prenatal diagnosis of microcephaly is not frequently and reliably made with confidence prior to the late second or third trimester at which time pregnancy termination is usually not available. Furthermore, false-positive diagnoses of microcephaly are not rare and can result in significant patient anxiety and possibly unwarranted pregnancy termination. A recent communication provides an algorithm for patients at risk for Zika. Two methods of testing are discussed, serology (IgM) and reverse transcriptase (RT)polymerase chain reaction (PCR). Detection of Zika RNA by RT-PCR is diagnostic. A positive IgM may not be diagnostic, because of cross-reactivity with similar viruses such as dengue. With both tests, there may be false negatives, which in the case of RT-PCR testing is due to rapid clearance of Zika RNA from maternal blood. An infection with Zika virus is asymptomatic in 4 of 5 patients. Although not proven, it is a reasonable assumption that Zika virus may be transmitted to the fetus in asymptomatic women. Thus an argument can be made that all pregnant patients with a history of recent travel to a geographical area where Zika is endemic could be tested. 97

Twin-to-twin transfusion syndrome

Twin-to-Twin Transfusion Syndrome (TTTS) is a rare placental disease that can occur at any time during pregnancy [5] involving identical twins. TTTS occurs when there is an unequal distribution of placental blood vessels between fetuses, which leads to a disproportionate supply of blood delivered. This unequal allocation of blood leads to developmental problems in both fetuses that can range in severity depending on the type, direction, and number of interconnected blood vessels.