Journal Club Papers
SARS-CoV-2 infection and COVID-19 vaccination rates in pregnant women in Scotland. Stock et al. Nature Medicine. 13 January 2022.
Review contributed by Dr Hannah Gordon.
As the Australian healthcare system faces the rapid spread of the Omicron SARS-CoV-2 (Covid) variant, this study from Stock et al. has come at an opportune time to inform clinicians about Covid infection and vaccination in pregnancy.
- This was a population-based cohort study from Scotland using data from 91,183 pregnancies between 1 December 2020 and 31 October 2021 to examine the impact of Covid during pregnancy and the effect of vaccination.
- During the study period, 4,950 women returned positive PCR tests to SARS-CoV2 (Wild-type, and Alpha or Delta variants). 16.6% (95%CI 15.6-17.7) required hospital admission, most commonly in the third trimester.
- Almost one in five (19.5%; 95%CI 18.3-20.8) unvaccinated women who contracted Covid during pregnancy required hospital admission, compared with 5.1% (95%CI 3.5-7.4) of women who were double vaccinated prior to infection.
- Of note, critical care admissions occurred in 2.1% (95%CI 1.7-2.6) of Covid-affected pregnancies, and 98.1% (95%CI 92.5-99.7) of those admitted were unvaccinated.
- The preterm birth rate was higher among women with Covid; 16.6% (95%CI 13.7-19.8) compared with 7.9% (95%CI 7.7-8.1) of women without Covid.
- The perinatal mortality rate (fetal death in utero ≥24 weeks gestation or death within 28 days of life) was 22.6 per 1,000 births (95%CI 12.9-38.5) for women within 28 days of Covid infection, compared with 5.6 per 1,000 births (95%CI 5.1-6.1) for Covid negative women.
- All women who experienced a perinatal death within 28 days of Covid infection (n=14) were unvaccinated.
- The paper also examines the uptake of vaccination by pregnant women in 144,548 pregnancies from 1 March 2020 to 31 October 2021.
- In 18,399 (20.2%) pregnancies, at least one dose of a Covid vaccine was administered, which is lower than the uptake among the general female population. Pregnant women who are younger (<20 years) and living in the lowest SES regions of Scotland are less likely to attend for vaccination.
Importantly, the paper makes no distinction between hospitalisations due to Covid, and hospitalisations of women with Covid. With the Omicron variant becoming dominant in Australia and around the world, it is uncertain whether the trends established in this paper will hold true for the current Omicron outbreak. This population-based study in Scotland reaffirms that Covid infection is associated with hospitalisation, preterm labour and perinatal mortality. But also, that vaccination is a powerful tool for reducing the likelihood of severe illness from Covid-19, with further benefit among those who receive two doses.
Association of Antenatal Diet and Physical Activity–Based Interventions with Gestational Weight Gain and Pregnancy Outcomes: A Systematic Review and Meta-analysis. Teede at al. JAMA Internal Medicine Dec 2021.
Obesity is now the most common medical condition worldwide and is projected to affect 21% of women globally by 2025. Previous large-scale meta-analyses have shown that gestational weight gain that exceeds international recommendations affects ~50% of pregnancies and is an independent risk factor for adverse maternal and neonatal pregnancy outcomes.
This systematic review aimed to evaluate the impact of different antenatal diet and physical activity-based interventions on gestational weight gain and maternal and neonatal outcomes.
Mean gestational weight gain (GWG) was the primary outcome. Secondary outcomes included gestational diabetes, hypertensive disorders of pregnancy, caesarean section, preterm delivery, large or small for gestational age neonates, neonatal intensive care unit admission, and fetal death.
117 RCTs (34, 546 women) of antenatal lifestyle interventions were analysed. The interventions were:
- Structured diet alone (dietary targets with or without monitoring)
- Structured physical activity alone (specific activity programs in controlled environments such as a gym or self-led activity programs with targets and equipment supplied)
- Diet with physical activity (one structured component but not both)
- Mixed interventions (unstructured lifestyle support, written information with weight monitoring, or behavioural support alone).
Compared with routine care, any lifestyle intervention resulted in reduced GWG (−1.15 kg; 95% CI, −1.40 to −0.91) and a reduced risk of gestational diabetes by 21% (odds ratio [OR], 0.79; 95% CI, 0.70-0.89) and total adverse maternal outcomes by 11% (OR, 0.89; 95% CI, 0.84-0.94).
Compared with routine care, structured diet alone was associated with less GWG (−2.63 kg; 95% CI, −3.87 to −1.40) than physical activity (−1.04 kg; 95% CI, −1.33 to −0.74) or mixed interventions (−0.74 kg; 95% CI, −1.06 to −0.43) and a reduced risk of:
- gestational diabetes (OR, 0.61; 95% CI, 0.45-0.82)
- preterm delivery (OR, 0.43; 95% CI, 0.22-0.84)
- large for gestational age neonate (OR, 0.19; 95% CI, 0.08-0.47)
- neonatal intensive care admission (OR, 0.68; 95% CI, 0.48-0.95)
- total adverse maternal (OR, 0.75; 95% CI, 0.61-0.92) and neonatal outcomes (OR, 0.44; 95% CI, 0.26-0.72).
Structured diet alone had no impact on risk of hypertensive disorders, caesarean section, fetal death or having a small for gestational age infant.
Structured physical activity alone was associated with less GWG (−1.04kg; 95%CI −1.33 to −0.74) and reduced risk of:
- gestational diabetes (OR, 0.60; 95% CI, 0.47-0.75)
- hypertensive disorders (OR, 0.66; 95% CI, 0.48-0.90)
- caesarean section (OR, 0.85; 95% CI, 0.75-0.95)
- total adverse maternal outcomes (OR, 0.78; 95% CI, 0.71-0.86)
Structured physical activity alone had no impact on risk of preterm birth, NICU admission or birth of a small or large for gestational age infant.
Diet with physical activity (one structured component) was associated with less GWG (−1.35 kg; 95% CI, −1.95 to −0.75) and reduced risk of:
- gestational diabetes (OR, 0.72; 95% CI, 0.54-0.96)
- total adverse maternal outcomes (OR, 0.81; 95% CI, 0.69-0.95).
Diet with physical activity had no impact on risk of hypertensive disorders, preterm birth, caesarean delivery, NICU admission or birth of a large or small for gestational age infant. Mixed interventions were associated with reduced GWG only. Overall, diet interventions had the greatest impact on GWG and were the only intervention to affect neonatal outcomes. The study concluded that there is strong evidence that antenatal structured diet and physical activity-based interventions are associated with reduced weight gain and lower risk of adverse maternal and neonatal outcomes. Widespread implementation of these interventions should be considered in antenatal care, with greatest support for diet-based interventions.
Association of Gestational Age at Birth With Subsequent Suspected Developmental Coordination Disorder in Early Childhood in China. Hua et al. JAMA Network Open. Dec 2021.
This was a retrospective cohort study in China examining children’s risk of Developmental Coordination Disorder (marked impairment of motor coordination) by gestational age at birth. The study included data from 2018-2019 on 152,433 children aged 3-5 years from 2,403 mainstream kindergartens in 551 cities throughout China.
Children’s motor performance was assessed using the Little Developmental Coordination Disorder (DCD) Questionnaire, completed by their parents.
Children born ‘completely full term’ (39 to 40 weeks’ gestation – 50.2% of total cohort) was the reference group against which all other groups were compared. The other comparison groups included: children born very preterm (<32 weeks – 3.6% of total cohort), moderately preterm (32-33 weeks – 1.5%), late preterm (34-36 weeks – 8.5%), early term (37-38 weeks – 25.5%), late term (40-41 weeks – 5.9%), and post term (>41 weeks – 4.9%).
Potential confounders were corrected for statistically. These included kindergarten cluster, child body mass index, maternal age, family structure and maternal pregnancy complications.
1) Preterm children:
Compared with children born at 39-40 weeks’ gestation, those born preterm all had an increased risk of motor coordination impairment: very preterm odds ratio [OR] 1.35 (95% CI, 1.23-1.48), moderately preterm (OR 1.18; 95% CI, 1.02-1.36) and late preterm (OR 1.24 (95% CI, 1.16-1.32).
Of note, early term, or 37-38 weeks’ gestation also incurred a greater risk: OR 1.11 (95% CI, 1.06-1.16).
2) Children born at term:
Compared with children born at 39-40 weeks’ gestation, those born late term (40-41 weeks) had the same risk but interestingly, those born post term (>41 weeks) had a raised risk of motor coordination impairment (OR 1.17; 95% CI 1.07-1.27).
The findings for very preterm children are perhaps unsurprising. The results around term gestation may be of interest to many generalists. First, it reaffirms why it is preferable to wait until 39 weeks’ gestation if possible, rather than 37-38 weeks. Second, the data suggests there are no childhood health benefits (in terms of motor coordination) from delaying induction until 42 weeks’ gestation. In fact, the outcomes appear to be worse.