A New Zealand study has linked maternal vaping and sudden infant deaths.
The study of 101 Sudden Unexpected Death in Infancy (SUDI) deaths in New Zealand in 2022 and 2023 had detailed information about maternal nicotine exposure and the infant’s sleep environment for 66 cases, the University of Auckland and University of Otago said in a joint statement.
“Maternal vaping is emerging as a potential risk factor for Sudden Unexpected Death in Infancy (SUDI) … [the] findings highlight the need to reassess public health messaging around vaping in pregnancy and bed sharing.”
The interaction between maternal smoking and bed-sharing was well-established, said the report’s lead author, Professor Ed Mitchell, of Waipapa Taumata Rau, University of Auckland.
“What is new and concerning is that vaping may be showing a similar pattern of risk as smoking, especially when combined with bed sharing.
“This raises the possibility that the effects of nicotine itself, rather than how nicotine is delivered, may be contributing to infant vulnerability.”
Smoking during pregnancy by mothers and sharing the bed with their baby are recognised major risk factors for SUDI, especially when they occur together, the researchers said.
Smoking in pregnancy had decreased in New Zealand, but SUDI rates remain the same.
The study of 101 SUDI deaths in 2022 and 2023 found smoking and/or vaping was reported in nearly three-quarters of these cases, while nearly 70% of infants had died while directly bed-sharing.
“Maternal vaping was reported in half of the SUDI cases involving direct bed sharing, compared with one in five cases where direct bed sharing was not reported.”
The study didn’t prove vaping caused SUDI, the researchers said.
But “uncertainty is not reassurance”, said co-author Professor Barry Taylor, of the University of Otago, Ōtākou Whakaihu Waka.
“When the possible consequence is an infant death, a precautionary approach is warranted while the evidence develops.”
The findings raised a fundamental question about current pregnancy advice, the researchers said.
“Vaping has been widely approached as a safer alternative to smoking and a smoking cessation aid, including in pregnancy”, Mitchell, the study’s lead author, said.
“Our findings suggest we need to consider all nicotine exposure during pregnancy, particularly when it is combined with bed sharing.”
In a related policy analysis published in the journal Acta Paediatrica, the same authors said pregnancy required a different approach to nicotine policy from that used for adults who are not pregnant.
Nicotine crossed the placenta, reduced foetal blood flow and lowered birth weights, Taylor said.
“We suspect that vaping may also produce the same infant ‘arousal defect’ seen with tobacco exposure.”
Early intervention key
The researchers recommended a pregnancy-specific approach with being nicotine-free as the goal, and co-ordinated support for women to achieve this across addiction services, pregnancy care, SUDI prevention and family support.
“Every woman who vapes or smokes during pregnancy needs support that meets them where they are in terms of their circumstances and confidence,” co-author Stephanie Cowan, of Change for Our Children, said.
“The aim is to help every woman move towards cessation as early as possible in pregnancy, because that is how both mother and infant are protected.”
In the SUDI cases studied, 84.8% of deaths occurring during direct bed-sharing involved maternal smoking or vaping.
More research was needed urgently to establish the specific risks associated with vaping during pregnancy, the researchers said.
“In the meantime … vaping, like smoking, should be discouraged in pregnancy and women should be supported to be nicotine-free as early as possible.”
Experts welcome findings
University of Auckland Liggins Institute Associate Professor Gergely Toldi said he also backed complete nicotine cessation being encouraged during pregnancy, breastfeeding and in households with babies aged under 1 “instead of recommending vaping as an acceptable alternative”.
Safe sleep principles from birth to 11 months also “cannot be overemphasised”, said Toldi, a consultant neonatologist at Starship Children’s Hospital.
“Direct bed sharing should be discouraged by all possible means.”
University of Auckland bioengineering institute Associate Professor Kelly Burrowes said it was important not to overstate the study’s findings.
“It is a case series without a comparison group, so it cannot establish that vaping causes SUDI or tell how much vaping independently increases the risk.
“Smoking, vaping, dual use and infant sleep practices can also overlap, making their individual effects difficult to separate.”
However, there was emerging evidence that vaping in pregnancy may lead to preterm birth and low birth weights.
“[The study’s] findings provide further reason to discourage vaping during pregnancy and to investigate its potential role in SUDI more urgently.
“Ideally pregnancy should be smoke, vape and nicotine-free, while people who smoke during pregnancy should continue to be supported with evidence-based cessation treatment.”
University of Otago Aspire Aotearoa tobacco control research centre Associate Professor Andrew Waa said they’d had success supporting mothers to quit smoking while pregnant.
But relapse after birth had “always been a challenge”, particularly if other family members continued to smoke.
“We need to ensure that government polices protect families from using cigarettes and vapes, rather than making them more available.
“We also need to make sure mothers and families are supported to quit both cigarettes and vapes.”