Pregnant Kailyn Lowry defended her reticence to go public with her baby reveal -- and it's not just mystery surrounding the baby daddy. The "Teen Mom 2" star is at high risk of miscarriage with this third child. She didn't want to go public and then lose the baby. Lowry assures everyone that she's happy to be expecting and this pregnancy was planned, though the reality TV star didn't say with whom. A high-risk pregnancy would explain Kailyn's early weight gain, after big weight loss. Common risk causes are anorexia, maternal obesity, gestational diabetes, edema and preeclampsia.

All Kailyn's plastic surgery could affect gestation too.

Obesity stalks Kailyn Lowry after weight loss

The "Teen Mom" boasted a 40-lb weight loss last year. Since her divorce from Javi Marroquin, Kailyn has been putting on the pounds. Fans wondered if weight gain meant Lowry was pregnant. But Lowry is probably only in her first trimester and not far enough along to have put on much. Women should only gain 25-35 pounds and most of it in the second and third trimesters. A risky pregnancy can cause abnormal weight gain but also loss. But usually it starts with obesity or anorexia. Maternal obesity endangers the fetus and the mother. And conversely, anorexia is problematic too. An eating disorder can make a mom-to-be eat too little and not gain enough weight.

Issues with 'Teen Mom 2' star's pregnancy

What is putting the reality television star at risk? It's not her age -- at 24, Lowry's in her prime pregnancy years. Beyonce is high-risk with being pregnant at 35 and with twins. If the reality television star is carrying multiples that would greatly multiply the danger. She hasn't named the baby daddy so there's always the chance she had some kind of IVF (invitro fertilization).

But, more common problems are maternal hypertension (high blood pressure) which can lead to life-threatening preeclampsia. Edema (unhealthy leg swelling) and varicose veins and obesity-related health concerns.

Miscarriage and other risks in Kailyn Lowry's pregnancy

The "Teen Mom 2" star has had a history of miscarriage. She didn't explain what conditions may have led to spontaneous abortion and may not know herself.

Most women never find out why their bodies don't or can't carry pregnancies. A few dangers are gestational diabetes. High blood sugar can put mom at risk of preeclampsia, placenta previa or placental abruption. These things can happen without predisposing factors. The recommendation is early detection and monitoring of health issues.