Updated 15 February 2021
In Part 1 of this special series, in which I’m covering recently-published research on all things related to pregnancy, birth and breastfeeding, I discussed the most important steps for women to take before they become pregnant.
Now, for Part 2, let’s dive into research on pregnancy and birth.
Pregnancy and birth
1. Having babies (and breastfeeding them) protects women against premature menopause
Given the physical and psychological stresses that pregnancy, birth and breastfeeding impose on women, it’s nice to know that child-bearing is not just an evil plot by Mother Nature to make us sacrifice ourselves for the good of the species. There’s something in it for us too. Aside from all the joys of motherhood – gazing into adoring eyes while breastfeeding, hearing the first attempts at ‘Mumma’, holding chubby little hands in yours – there are numerous health benefits of bearing offspring.
Evidence is accumulating that motherhood protects against premature menopause. This is vitally important, because women who go through menopause before the age of 45 are at increased risk of premature death, cognitive decline, osteoporosis, and cardiovascular disease.
According to recent findings from the Nurses Health Study II (a large cohort study which has been tracking the health of female US nurses for several decades), women who have 1 pregnancy lasting for at least 6 months have an 8% lower risk of premature menopause than women who have never been pregnant. For 2 pregnancies, the risk is reduced by 16%; for 3 pregnancies, 22%, and for 4 pregnancies, 19%.
Breastfeeding was also found to reduce the risk of early menopause.
2. Avoid excessive weight gain during pregnancy
A study of over 15 000 children from Shanghai, China found that those whose mothers gained the most weight during pregnancy had the highest risk of developing allergic diseases – especially if the mothers were already overweight or obese before becoming pregnant – while those whose mothers gained less than the amount recommended by the US Institute of Medicine (IOM) had a reduced risk of allergic disease.
The highest amount of pregnancy weight gain was associated with:
- 42% higher risk of childhood asthma/wheezing
- 32% higher risk of allergic rhinitis
- 24% higher risk of eczema.
In women who were of normal weight or were underweight before pregnancy, gaining less weight than recommended by the IOM was associated with:
- 13% lower risk of childhood asthma/wheezing
- 11% lower risk of allergic rhinitis
- 14% lower risk of eczema
- 15% lower risk of food/drug allergy.
Unfortunately, in women who were overweight or obese before pregnancy, gaining less than the recommended amount of weight during pregnancy did not appear to protect their children against developing allergic disease, highlighting the importance of attaining a healthy weight before beginning your family.
Obesity during pregnancy has also
3. For a brighter baby, eat fruit during pregnancy
The interminable ‘diet wars’ have generated enormous confusion in the public (and quite frankly, among many poorly-informed health and medical professionals) about the health properties of natural sources of carbohydrate, including fruit.
Many of my clients have been told by other practitioners to limit their fruit consumption ‘because fruit is full of sugar’. The absurdity of equating the sugars found naturally in whole foods like fruit, with refined sugars found in processed foods, should be obvious, but apparently to many people it is not.
However, women who avoid fruit during pregnancy may be disadvantaging their child’s brain development. In a substudy of the Canadian Healthy Infant Longitudinal Development (CHILD) study, mothers who ate more fruit during pregnancy had children who did better on developmental testing at 1 year of age.
In fact, for each additional serving of fruit (sum of fruit plus 100% fruit juice) that women consumed each day during pregnancy, their child scored 2.38 points higher on the Bayley scale of infant development (BSID-III), a well-validated instrument of cognitive development for infants.
The researchers validated their findings in fruit flies and, more recently, rats, finding improved learning and memory consolidation in offspring of both species whose mothers consumed fruit juice during pregnancy.
4. Consuming caffeine during pregnancy has long-term harmful effects on your baby’s brain and behaviour
Pregnant women have long been advised to moderate their caffeine intake. However, according to the lead investigator of a study which assessed the effect of mothers’ caffeine consumption during pregnancy on the structure of their children’s brains, and their neurodevelopmental outcomes,
“Any caffeine during pregnancy is probably not such a good idea.”
John Foxe, Ph.D.
Foxe and his team examined magnetic resonance imaging (MRI) scans collected from over 9000 children aged 9-10, and compared differences in the organisation of white matter tracts – the connections between brain regions – with the children’s mothers’ self-reported intake of caffeine whilst pregnant with them.
The researchers identified clear alterations in the formation of two key tracts in the brains of children whose mothers reported having consumed caffeine during pregnancy.
Furthermore, these alterations in brain development were correlated with poorer outcomes on assessments of the children’s neuropsychological outcomes, including:
- Externalisation (tendency toward aggressive, disruptive and destructive behaviours);
- Internalisation (tendency toward depression, anxiety, irritability, social withdrawal, substance abuse, feelings of loneliness, guilt and sadness, difficulty concentrating, and negative self-talk),
- Somatisation (tendency toward experiencing and communicating psychological distress in the form of somatic symptoms such as headaches and upset stomach); and
- Neurodevelopment (age-appropriate development of the nervous system).
Many women develop a strong aversion for the smell and taste of coffee during pregnancy, and it seems that following their maternal instincts and avoiding caffeine altogether, might be a good idea!
5. Exercise during pregnancy protects both mother and baby against obesity
Admittedly, this next study was performed in mice rather than humans, but the findings are intriguing: lean mice who were exercised daily during their pregnancies:
- Gained less weight than pregnant mice who were kept sedentary, despite eating the same amount of food;
- Had lower blood glucose levels and less insulin resistance (i.e. they were protected against gestational diabetes);
- Developed more brown fat (the type of fat that actually burns calories) and less white fat (plain old fat, that stores calories); and
- Lost their ‘baby weight’ faster after giving birth, and while lactating.
The babies born to mice who were exercised while pregnant had less white fat and more brown fat than babies of sedentary mouse mothers, as well as increased activity of fat-burning enzymes.
Brown fat is critical for temperature regulation in newborns, because they are unable to raise their body temperature by shivering when they’re cold). The baby mice whose mothers exercised during pregnancy had a better brown fat response to cold exposure, indicating that their mothers’ fitness gave them a significant survival advantage.
When deliberately overfed on a high fat diet, mice from exercising mothers ate more food but gained less body fat and had better insulin sensitivity than mice born to sedentary mothers, and female offspring of exercising mice also gained less weight.
While these findings obviously need to be confirmed in humans, the take-home message for now is that women should continue to exercise throughout their pregnancies (or begin exercising, if they’ve previously been sedentary) unless they develop a condition that makes exercise unsafe for themselves or their unborn child.
6. Caesarean delivery should be avoided unless truly necessary
While caesarean delivery can be life saving for mother, baby, or both in certain circumstances, many c-sections are performed without a clear medical reason.
The procedure has long been known to be hazardous for the mother – a 3-fold greater risk of major adverse birth outcomes including cardiac arrest, hysterectomy, puerperal infection, and thromboembolism – but evidence of lifelong harm to babies born by c-section is rapidly accumulating.
In another substudy of the Nurses Health Study II, women born by cesarean vs vaginal delivery had an 11% higher risk of becoming obese than women born vaginally, after statistical adjustment for known confounding factors including their mother’s age at delivery, race/ethnicity, educational level, and mother’s gestational weight gain and gestational diabetes status.
The risk of developing type 2 diabetes was 46% higher in women born by caesarean vs vaginal delivery even after additional adjustment for participant’s own body mass index – that is, even lean women were at increased risk of becoming diabetic if they had been born by c-section.
The increased risk of obesity and diabetes was evident even in women whose mothers had no traditional risk factors for c-section (i.e. prepregnancy BMI <25, no gestational diabetes, no hypertensive disorders of pregnancy, no smoking during pregnancy, maternal age <30 years, gestational age at delivery between 37 and 42 weeks, and birth weight between 2.3 and 4.4 kg).
The researchers speculated that the increased risk of obesity and diabetes in women born by caesarean delivery may be due to the less diverse gut microbiota observed in infants who are deprived of normal vaginal birth.
Furthermore, women appear to have lower fertility after undergoing a c-section delivery than after giving birth vaginally. The First Baby Study found that among 2021 women who had unprotected intercourse during the 3 years after they had their first baby, those who had had a caesarean delivery were 15% less likely to conceive (regardless of whether or not they were trying to conceive) and 17% less likely to have a subsequent live birth than women who gave birth vaginally.
Women who had delivered by caesarean had a subsequent stillbirth rate of 1.2% compared to 0.1% in those who birthed vaginally.
Caesarean delivery should never be framed as an ‘easier option’ for pregnant women who are fearful of the travails of vaginal delivery, nor should it be done for the convenience of obstetricians.
It carries serious risks for the health and fertility of women, and the lifelong health of their babies.
7. Don’t stress about COVID-19
Despite widespread scaremongering about the risks posed by SARS-CoV-2 infection to pregnant women and their babies, an international study which included data on 666 newborns and 655 women has found that:
“Neonatal COVID-19 infection is uncommon, almost never symptomatic, and the rate of infection is no greater when the baby is born vaginally, breastfed or allowed contact with the mother.”
maternal transmission of SARS-COV-2 to the neonate, and possible routes
for such transmission: A systematic review and critical analysis
Just 28 of the 666 newborns were found to have a confirmed SARS-CoV-2 infection; of these, only 8 had symptoms and in 4 of these, the symptoms may have been related to prematurity (unrelated to COVID-19).
Pregnant women have enough to worry about, with being scared senseless by the relentless COVID-19 fear-porn spewing forth from the media and many so-called health experts. Obviously, sensible measures should be taken to protect one’s health during pregnancy, including hand hygiene and avoidance of people with respiratory or other infections.
8. Do not take antidepressants during pregnancy
As discussed in Part 1, the children of women who took a selective serotonin reuptake inhibitor (SSRI) or selective serotonin norepinephrine inhibitor (SNRI) antidepressant while pregnant with them, have been found to had roughly 40% higher odds of showing two or more developmental vulnerabilities, and in particular, deficits in language and cognition, as assessed by the Early Development Instrument (EDI).
Taking antidepressants during pregnancy causes alterations in the unborn baby’s brain that may have lifelong harmful effects.
In Part 3, we’ll delve into recent research on breastfeeding.
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