Journal Club Papers
The effect of two midwives during the second stage of labour to reduce severe perineal trauma (Oneplus): a multicentre, randomised controlled trial in Sweden. Edqvist et al. The Lancet. 15 March 2022.
This multi-centre randomised controlled trial aimed to determine whether the presence of two midwives, rather than one, during the second stage of labour reduces the rate of severe perineal trauma in spontaneous vaginal birth among nulliparous women.
3,776 eligible women were recruited from five obstetric units across Sweden.
- Exclusion criteria were multiparous women, preterm (<37 weeks) gestation, multiple pregnancy, intrauterine fetal demise or planned caesarean section.
- Allocation to the intervention was randomised but not blinded (hard to hide an extra midwife in the room!) – the statistician was blinded to the allocation.
- Women were assigned to standard care (one midwife, performing usual perineal protection techniques) or intervention (an additional midwife supporting the primary midwife in providing appropriate perineal protection).
- Perineal trauma prevention techniques included delayed pushing, manual perineal protection, warm perineal compresses, perineal massage and protection of the shoulders.
An intention-to-treat analysis was performed, which included only women who had a spontaneous vaginal birth. The primary outcome was the proportion of women who sustained severe perineal trauma (tears involving the anal sphincter complex).
The unadjusted odds of severe perineal trauma were reduced by 32% among the intervention group (61 of 1546 (3.9%) vs 86 of 1513 (5.7%) women; OR 0.68; 95%CI 0.49-0.95).
- There was no difference between the intervention and standard care groups with regards to episiotomy rate, birth position, duration of first stage of labour, post-partum haemorrhage >500ml, low Apgar score or admission to the NICU.
- The duration of active second stage of labour was marginally longer in the intervention group (34 vs 33 minutes, p=0.033).
- The majority of second midwives in the intervention group (77.1%) were present in the birth room for 30 mins or less.
- Although excluded from the final cohorts, instrumental and caesarean births were the same between the intervention and standard care groups.
The authors suggest that the intervention worked as a behaviour change strategy, namely through observation, peer support and feedback. By providing improved communication with the woman in labour for example, the presence of a second midwife was thought to be preventive against severe perineal trauma.
There was no cost-benefit analysis performed however the study was done within existing hospital budgets with no additional midwives employed. This was in the hope of showing that it could be widely translatable into practice.
The authors concluded that the presence of two midwives at birth reduce the risk of several perineal trauma for women having their first vaginal birth but did not change any other maternal or neonatal outcomes.
Durability of Anti-Spike Antibodies in Infants After Maternal COVID-19 Vaccination or Natural Infection. Shook et al. JAMA. 7 February 2022.
This case series assessed SARS-CoV-2 antibody response in newborns whose mothers were either vaccinated against or infected with COVID-19 during pregnancy.
- Eligible women were vaccinated (with no prior SARS-CoV-2 infection) or had been infected between 20 – 32 weeks’ gestation. Matched maternal and umbilical cord serum were collected at birth and again in infants at 2 and 6 months.
- 77 mRNA COVID-19 vaccinated, and 12 symptomatic SARS-CoV-2 infected women were included.
- Compared with SARS-CoV-2 infected mothers, antibody titres at birth were significantly higher in both maternal serum (optical density 2.03 [SD0.47] vs 0.65 [SD 0.76, p<0.001) and cord serum (2.17 [SD 0.50] vs 1.0 [SD 0.83], p<0.001) among vaccinated mothers.
- At 2 months, 98% (48/49) of the infants of vaccinated mothers had detectable antibody titres. Levels correlated with maternal and cord titres at birth. 2-month blood samples were not collected from the infected group.
- At 6 months, 57% (16/28) of the infants born to vaccinated mothers had detectable antibody levels compared with just 8% (1/12) of infants born to infected mothers.
Although clinical immunity to COVID-19 was not assessed, these findings suggest that infants born to mothers who are vaccinated during pregnancy have a more robust and persistent antibody response than those born to mothers infected by COVID-19 during pregnancy.
There is now reassuring evidence of COVID-19 vaccination safety during pregnancy. This includes studies previously covered by the JCOTR team and more recent studies of large cohorts (158,000 and 98,000 women) showing that COVID-19 vaccination is not associated with adverse perinatal outcomes (Association of SARS-CoV-2 Vaccination During Pregnancy With Pregnancy Outcomes (Magnus et al.) and Association of COVID-19 Vaccination in Pregnancy With Adverse Peripartum Outcomes (Fell et al.)).
These safety findings and the evidence of an enduring antibody response in infants should be used to encourage pregnant women to get vaccinated for both their own and their newborns’ benefit.
Association between maternal thyroid function and risk of gestational hypertension and pre-eclampsia: a systematic review and individual-participant data meta-analysis. Toloza et al. Lancet Diabetes Endocrinology. 4 March 2022.
Review contributed by Alexandra Roddy Mitchell (Mercy Perinatal PhD candidate & Midwife) This systematic review and individual participant data meta-analysis examined the associations between maternal thyroid function and gestational hypertension, or pre-eclampsia. 19 cohort studies and a total of 46 528 pregnant women were included, with individual participant data available for 39 826. Thyroid function was assessed via thyroid-stimulating hormone (TSH) and free thyroxine (FT4) concentration and thyroid peroxidase antibody status. Of those women with individual level data, 1275 (3.2%) had subclinical hypothyroidism, 933 (2.3%) had isolated hypothyroxinaemia, 619 (1.6%) had subclinical hyperthyroidism and 337 (0.8%) had overt hyperthyroidism. Subclinical hypothyroidism was defined as a TSH concentration above the 97.5th percentile and an FT4 concentration within reference range (2.5th percentile – 97.5th percentile). In Australia, depending on the assay used, the 97.5th centile for TSH lies between 3-4 in first trimester, 3.2-4.2 in the second trimester, and 3.5-4.2 in the third trimester.
- Compared with euthyroidism, subclinical hypothyroidism was associated with a 53% increase in the likelihood of pre-eclampsia (3.6% vs. 2.1%, odds ratio [OR] 1.53 [95% CI 1.09 – 2.15]) but not associated with gestational hypertension (OR 1.18 [0.91 – 1.53]).
- Subclinical hypothyroidism was also associated with an increased likelihood of the composite outcome of either pre-eclampsia or gestational hypertension (OR 1.45 [1.14 – 1.53]).
- Overt hyperthyroidism (n=337) was not associated with pre-eclampsia (2.9% vs. 2.1%, OR 1.43 [0.70 – 2.92) or gestational hypertension (6.0% vs. 4.2%, OR 1.59 [0.97 – 2.60]). However, it was associated with an increased likelihood of the composite outcome, pre-eclampsia or gestational hypertension (9.3% vs. 5.6%, OR 1.90 [1.21 – 2.99])
- Subclinical hyperthyroidism and isolated hypothyroxinaemia were not associated with pre-eclampsia or gestational hypertension.
- TSH analysed on a continuous scale was associated with pre-eclampsia, with both low and high concentrations associated with an increased likelihood of pre-eclampsia (p=0.0001).
This study shows that compared to euthyroidism, subclinical hypothyroidism is associated with an increased likelihood of developing pre-eclampsia, as are both higher and lower concentrations of TSH. The authors conclude that these findings have implications for defining an optimal TSH target for treatment with thyroxine during pregnancy.
However, it may be important to note that it remains unproven whether correcting the subclinical hypothyroidism with low dose thyroxine can reduce this increased risk of preeclampsia.
Currently RANZCOG and ACOG do not recommend universal screening of thyroid function in pregnancy or treatment for subclinical hypothyroidism in an otherwise uncomplicated pregnancy.