A reasoned approach towards administering COVID-19 vaccines to pregnant women.

There are over 50 SARS-CoV-2 candidate vaccines undergoing Phase II and III clinical trials. Several vaccines have been approved by regulatory authorities and rolled out for use in different countries. Due to concerns of potential teratogenicity or adverse effect on maternal physiology, pregnancy has been a specific exclusion criterion for most vaccine trials with only two trials not excluding pregnant women. Thus, other than limited animal studies, gradually emerging development and reproductive toxicity data, and observational data from vaccine registries, there is a paucity of reliable information to guide recommendations for the safe vaccination of pregnant women. Pregnancy is a risk factor for severe COVID-19, especially in women with comorbidities, resulting in increased rates of preterm birth and maternal morbidity. We discuss the major SARS-CoV-2 vaccines, their mechanisms of action, efficacy, safety profile and possible benefits to the maternal-fetal dyad to create a rational approach towards maternal vaccination while anticipating and mitigating vaccine-related complications. Pregnant women with high exposure risks or co-morbidities predisposing to severe COVID-19 infection should be prioritised for vaccination. Those with risk factors for adverse effects should be counselled accordingly. It is essential to support patient autonomy by shared decision-making involving a risk-benefit discussion with the pregnant woman.

Management of overt hypothyroidism during pregnancy.

Overt hypothyroidism is a common endocrine disorder affecting 1-2% of women of reproductive age. Optimizing treatment in pregnant women with overt hypothyroidism can reduce adverse fetal and maternal outcomes. Ideally, women who are known to have a history of hypothyroidism or those with risk factors for becoming hypothyroid, should have adequate preconception care to ensure euthyroidism from the onset of pregnancy, with a TSH target of below 2.5mIU/L. On women who are already on levothyroxine, an empirical dose increase of 30-50% as soon as pregnancy is confirmed may be considered. During pregnancy, levothyroxine doses should be titrated against TSH, which have trimester-specific ranges. In women who are known to be hypothyroid but are inadequately treated, we recommend a doubling of levothyroxine dose on at least three days a week to rapidly achieve euthyroidism. In newly diagnosed overt hypothyroidism in pregnancy, starting doses of either 100 or 150 mg daily may be considered safe.

Trends and predictors of cesarean birth in Singapore, 2005-2014: A population-based cohort study.

BACKGROUND: Rates of cesarean birth have continued to rise in many high-income countries. We examined the temporal trends and predictors of cesarean birth in Singapore. METHODS: Linked hospitalization and Birth Registry data were used to examine all live births to Singaporean citizens and permanent residents between January 1, 2005 and December 31, 2014 (n = 342 932 births). We calculated cesarean rates and age-adjusted average annual percent change (AAPC) in those rates and used sequential multivariable regression modeling to assess the contribution of changes in predictors to the change in cesarean rates over time. RESULTS: The overall cesarean rate in Singapore rose from 32.2% in 2005 to 37.4% in 2014. Among singleton, cephalic, term pregnancies, the two major predictions of cesarean were nulliparity and previous cesarean, each accounting for just over one-third of all cesareans. Higher AAPC was observed in nulliparous women of Indian ethnicity (0.74% [95% confidence interval 0.68-0.80]) compared with Chinese (0.62% [0.60-0.65]) or Malay women (0.63% [0.59-0.68]), and in women who delivered in private hospitals (0.62% [0.60-0.64]) compared with those delivered under subsidized care in public hospitals (0.58% [0.52-0.63]). Parity and education had the largest influences on cesarean birth trend (attenuation of AAPC from 0.62% [0.59-0.66] to 0.39% [0.38-0.40] after adjustment). CONCLUSION: Cesarean birth has continued to rise at a steady rate in Singapore. Strategies to curb this temporal increase include avoidance of medically unnecessary primary cesarean and attempts at trial of labor and vaginal delivery among women with a history of prior cesarean.

The assessment of combined first trimester screening in women of advanced maternal age in an Asian cohort.

INTRODUCTION: First trimester screening (FTS) is a validated screening tool that has been shown to achieve detection rates of 84%-90% for trisomies 21, 18 and 13. However, its effectiveness for different maternal ages has not been assessed. The present study aimed to assess the performance of FTS in an Asian population, and to compare its effectiveness in older (≥ 35 years) and younger (< 35 years) women. The potential use of noninvasive prenatal test (NIPT) as a contingent screening test is also examined. METHODS: Data on cases of FTS performed on singleton pregnancies over a six-year period was collated from two Singapore maternal centres, National University Hospital and Singapore General Hospital. Cases that had a 1:250 risk of trisomy were considered to be screen-positive. Pregnancy outcomes were obtained from birth records or karyotype test results. RESULTS: From 10,289 FTS cases, we obtained a sensitivity of 87.8%, a specificity of 97.6%, a false positive rate of 2.4% and a false negative rate of 0.06% for the detection of aneuploidy. The overall detection rate for trisomy 21 was 86.5%-85.7% for older women and 87.5% for younger women. The mean number of invasive tests required per case of trisomy 21 was 9.3 in younger women, 8.6 in older women and 13.5 in women with intermediate risk (1:250-1,000). CONCLUSION: While the performance of FTS was similar in younger and older women, more invasive procedures were required to diagnose trisomy 21 in women with intermediate risk. It may be advantageous to offer contingent NIPT to this group of women to reduce the risk of iatrogenic fetal loss.