Monkeypox in pregnancy: update on current outbreak

The monkeypox case count in the current global outbreak surpassed 52 000 on Sept 1, 2022. Community transmission is affecting people considered to be at high risk of severe disease, including pregnant women and neonates, albeit in small numbers so far. As of Sept 2, 2022, ten cases of monkeypox in pregnant women have been reported worldwide, mostly via local news media rather than medical or public health publications, with the first case reported in the USA on July 23, 2022.¹ Based on available information, vertical transmission did not occur; the neonate received prophylactic vaccinia immunoglobulin and did not develop monkeypox disease.

On Aug 4, 2022, the Government of São Paulo, Brazil, announced that two pregnant women had been diagnosed with monkeypox and were being monitored by health-care professionals.2, 3 By Aug 26, the Brazilian health authorities had reported a total of nine cases in pregnancy (four in São Paulo, three in Rio de Janeiro, one in Minas Gerais, and one in Ceará).² Eight had monkeypox PCR-confirmed by Sept 1, whereas the woman in Ceará tested negative.² On Aug 5, a local newspaper in São Paulo reported that one of the infected pregnant women had passed the transmission phase, with both mother and baby in a stable condition, but there was no information on vertical transmission.⁴ In Minas Gerais, the 26-year-old pregnant woman with monkeypox presented to hospital with skin lesions on Aug 4 and gave birth to a healthy infant on Aug 14.⁵ She was isolated from her baby after birth and discharged healthy on Aug 17. There was no vertical transmission; the neonate was asymptomatic but remained in hospital when the mother was discharged.

Reassuringly, it appears that, so far, none of the monkeypox infections reported in pregnant women have been severe, and there has been no evidence that pregnant women have more severe disease or worse outcomes than non-pregnant people. There is, however, an urgent need for an international registry or reporting system to better understand the course, management, treatment, and outcomes of monkeypox, as well as the safety and effectiveness of vaccination, in populations at high risk, including the mother–fetus dyad, so that patients worldwide can be provided with accurate advice and evidence-based care. Unfortunately, we are currently having to rely on news outlets providing sparse information that is not externally verifiable. Nevertheless, a higher number of monkeypox infections in pregnancy have now been reported in non-endemic versus endemic countries, highlighting decades of neglect by international communities of such infectious diseases in endemic countries. If there are lessons to be learnt in the current monkeypox outbreak, we are failing to learn them.

AK and PO'B are members of the Royal College of Obstetricians and Gynaecologists' group developing guidance on monkeypox in pregnancy. PO'B is Vice-President of the Royal College of Obstetricians and Gynaecologists. All other authors declare no competing interests.