Some spices could cause miscarriage or early pregnancy loss, but not because of their spicy flavor. Many spices and herbs stimulate uterine contractions or uterine bleeding, which can cause very early miscarriage or later pregnancy loss. Cooking with spices isn't dangerous in pregnancy; only supplements are potent enough to potentially cause problems, so do not take supplements containing herbs or spices without your doctor's approval.
Spices that can cause miscarriage fall into two general categories: abortificients, substances that can cause uterine contractions that might induce miscarriage, and emmenagogues, substances that bring on a menstrual period. Emmenagogues might interfere with a very early pregnancy by not allowing the embryo to implant, while abortificients stimulate the uterus. Contractions could disrupt a pregnancy or cause preterm labor. Some midwives and alternative practitioners may recommend taking certain spices and herbs after 36 weeks of pregnancy to "tone" the uterus for labor, the Perinatal Education Associates website states.
Numerous spices can cause uterine stimulation and contractions in concentrated doses. Avoid anise, basil, caraway, cayenne pepper, celery seed, chili powder, cinnamon, clove oil, cumin, marjoram, oregano, parsley, rosemary, sage and thyme in large quantities. Other herbs to avoid in concentrated quantities include angelica, bitter orange, chamomile oil, fenugreek, lavender, parsley and peppermint oil. Talk with your doctor before you take any herbs or spice supplements.
Spices That Induce Menstruation
Spices that could disrupt an early pregnancy by starting your menstrual period include saffron, safflower, wild ginger and turmeric. Emmenagogues are normally used to regulate menstrual cycles but could be risky if you don't realize you're pregnant because you haven't missed a menstrual period yet.
The Spice Effect
You may worry about the effect spicy or hot foods will have on the pregnancy or on your baby. Spicy foods will not cause uterine contractions or harm your pregnancy in any way, obstetrician Dr. Carol Archie of the University of California and infertility specialist Dr. Mary Lake Polan explain on the BabyCenter website. They may, however, cause heartburn, which could increase your discomfort in pregnancy. Most herbs and spices have not been tested for their effects as supplements during pregnancy, so don't assume that any supplement is safe to take without asking your doctor first.