Originally Posted by Bandito
Most women do in fact reach ketosis while pregnant. They can't keep anything down due to morning sickness, and the body burns ketones as a rusult. This often lasts for 12 weeks during the time that the baby undegoes the most cellular differentiation, the same time the baby is most suseptable to environmental influences.
I'm not sure who told you that early in pregnancy *most* women are in ketosis because of morning sickness, or any other reason, but it's simply not true - even if they're controlling carbohydrate as long as they're eating about 72g of carbs a day (net minus fiber) or more. Pregnancy does indeed induce ketosis late in pregnancy - it's simply not an issue for the vast majority in the first trimester or well into the second.
Whether ketosis - and let's be clear here, I'm talking continuous ketosis
, not the very normal tettering ketosis that almost all pregnant women will experience later in their pregnancy - is harmful to human pregnancy is unknown.
Animal models are clear - continuous
ketosis is harmful to an embryo, a fetus and a breastfed baby animal receiving milk from its mother in ketosis. The list of "unfavorable outcomes" range from birth defects to failure to grow properly in utero, from liver problems to lower milk production and poor energy utilization, from inadequate nutrient supply to low bone density in the baby animal, from higher rates of spontaneous abortion (miscarriage) to pre-term labor resulting in low birth weight animals.
These are serious issues and if the animal model even begins to touch on the risks to a human pregnancy, it's clear that one does not want to be in continuous ketosis while trying to get pregnant, when pregnant or when lactating....it's too risky given the large amount of data known in the animal model.
On the other hand, ketosis - that is tettering in and out of ketosis - while pregnant does not appear to be a negative, is part-and-parcel to the later part of pregnancy, and in fact, during labor most likely is important for the mother to have the energy to go through labor and delivery when eating becomes a real challenge (most doctors won't let you eat anyway, but even if you try to eat, odds are you're just going to throw it up).
When DH and I were TTC, I was already eating "controlled-carb" since I'd been maintaining my weight loss for more two years at the time - so I wasn't at risk for continuous ketosis since I was above the usual 60g net threshold for continuous ketosis.
When I did get pregnant, my OB gave his blessing to continue eating controlled-carb, warned I'd gain more weight than an "average" pregnancy even with controlling carbs (which I did) and only made me promise not to dip below 70g of carbs each day (net minus fiber) through my first two trimesters and increase to at least 100g of carbs (net minus fiber) in the last trimester IF I was in ketosis more than not - I wasn't, but I wound up eating more carbs anyway - averaged probably 125g a day (net minus fiber).
Provided that mom is being adaquetly nourished, I dont see what detrimental effects ketosis would have on pregnancy. If there was, wouldn't it show up in these critical weeks?
If it did show up it would be a miscarriage and there simply isn't data to support the assumption
that continuous ketosis doesn't factor into the picture or is harmless. What the data does show is that ketosis inhibits appetite, resulting in eating less calories - pregnancy requires more calories and if you're having a hard time getting them in at a level to maintain weight, wouldn't you think it would be more difficult to increase calories to support a pregnancy too?
Add to that, low-carb diets are often inadequate for critical essential nutrients. Sure you can pop a multivitamin, but no one is going to argue that food is your best source for essential nutrients since food also is packed with the co-factors and a spectrum of nutrients that complement each other together rather than in isolation. Unless you're really careful and know how to plan to meet pregnancy requirements with your diet, you're going to be robbing your body and the growing fetus of nutrients you need.
Then there's the issue of glucose requirements for the fetus - if you're not eating enough carbohydrate to support the glucose requirement of the baby, you're going to be making it with gluconeogenesis from protein. Considering our finite capacity for eating protein, you're taking a risk here since if you simply "hit the protein wall" before you eat enough protein for GNG, you're going to cannibalize your muscle to make glucose for the baby - no way around it.
There's also the issue of ketones passing to the baby for energy utilization - from animal models it does not appear that the developing fetus can use the maternal ketones for energy and the data shows they build up in the developing fetus liver, leading to malformations of the liver and/or jaundice at birth. Is that a risk you'd want to take? I don't think so...
Given the potential risks - I totally agree with the recommendation most OB's (who are open to or advocate controlled-carb) make to increase carbs to a certain level to avoid continuous ketosis...we simply don't have any data to suggest it's harmless in pregnancy from day one. Increasing carbs up to a level to avoid continuous ketosis isn't license to eat whatever - just make good choices and include some foods that are higher in carbs but still nutrient-dense, like sweet potatoes or legumes.