Running During Pregnancy: Half Marathon Safety at 19 Weeks

Question
Hello,
I am an experienced runner.  I ran two marathons last year and maintained my running at a lower (15km long runs weekly) after the marathons.  I have been keeping up my running during my pregnancy.  I am 19 weeks pregnant now and am wondering about the safety of running a half marathon in a week from now.  I have been feeling aches in my lower abdomen/pelvic bone after a long run, but the pain subsides after I rest.  I have also felt a few jabbing pains on one side of my tummy (not during a run) and those came and went quickly.  Is this normal pregnancy discomfort or is it a result of my running?  Should I discontinue/back off my running for the remainder of the pregnancy?  What are the risks to the baby and myself If any.

Thanks

Answer
Because you have maintained a very high fitness level before and during this pregnancy, your body is well acclimated to running at both the volume and intensity that a half marathon requires.

The placenta stops growing at 20 weeks gestation, and at this point is at its maximal capacity for the exchange of oxygen, nutrients, and waste products. Your high fitness level has resulted in a placenta that is bigger and more efficient than most. And your baby has in fact been "working out" with you, and has a much stronger, more efficient cardiovascular system than most. For these reasons, a half marathon will not overtax your cardiovascular system.

However, you should take special precautions. Keep you fluid intake high, and drink at regular intervals even though you might not feel thirsty. Keep your carbohydrate levels even, before, during and after the run. Don't try to do the event without food/supplementation.

Be alert for adverse weather conditions. If it is sunny, dry and hot, or humid and hot, you body will be much more effected and you may find your perceived exertion level to be much higher than normal. Be prepared to not finish the race under these conditions. If at any time, for any reason, you feel like you are "running on empty" than this is a signal to stop. Non pregnant athletes can push through the fatigue/pain, you should not.

From twenty weeks onward all women should slowly begin to taper down the intensity of their aerobic activities. And since your baby grows more rapidly and begins to demand more and more oxygen in the last half of pregnancy, your rate of perceived exertion for any given activity will continue to rise. Not matter what fitness level, all pregnant women should stay in a moderate aerobic training zone. Never get to the point of panting.

Achiness in the pelvic bone is a red flag for possible pelvic instability. Pregnancy hormones soften ligaments in preparation for childbirth. Sometimes the ligament that connects the right and left pubic bone, the pubis symphasis, gets too loose, and this normally fused joint can become unstable. High impact running may cause or worsen the condition. If you continue to feel pain at this joint you should stop running and switch to non-impact exercise. Many pregnant athletes switch to swimming in the last half of pregnancy. It provides a great cross training benefits with little to no stress on joints.

Pelvic instability is a clear contraindication for running. Use common sense judgement here. If your pelvis/pubic pain occurs after every run, then I would advise you not to do the half marathon.

The jabbing pain on one side of the tummy is due to stretching of the round ligament, a common midpregnancy discommfort. To relieve pain, perform a "hip hiker" on the painful side. Stand adjacent to a countertop and place one hand on countertop for balance. Lift the foot of the painful side off the floor a few inches. Then lift your hip on the painful side closer to your armpit. This takes the tensile forces off the ligmant and provides immediate relief. Perform several times daily, or as necessary.