Pregnancy after Bariatric Surgery
Commentary
Mervyn Deitel, MD
Toronto, Canada
Massively obese individuals have a decreased level of sex
hormone-binding globulin (SHBG), which acts as a plasma transport protein. This
,6-globulin binds testosterone strongly and estradiol weakly. With the decreased
level of SHBG in the obese, circulating androgens are relatively increased. The
androgens are converted to estrogens in the stroma of the adipose tissue (which
is plentiful in the obese) by a process of aromatization.) 3 Thus, massively
obese women have elevated levels of both free androgens and estrogens. This
results in hirsutism. Importantly, the elevated estrogens lead to endometrial
hyperplasia and an increased incidence of cancer of the breast and of the
uterus. The sex hormone abnormalities also result in irregular periods,
oligomenorrhea or amenorrhea, anovulatory cycles, and infertility. These
features are reversed as the sex hormonal levels normalize after loss of the
massive excess weight.2, 4
The obese also have an increased incidence of gestational diabetes and
hypertension, as well spontaneous abortion, pre-eclampsia, Cesarean section,
macrosomic neonates, and a slightly increased incidence of deep-vein thrombosis
during pregnancy.5 6 However, with pregnancies after loss of the excess weight,
these co-morbidities are no longer increased.It was recommended that after
jejunoileal bypass JIB) pregnancy should be delayed for 18 months in
order to avoid the malnutrition and small-for-dates features in the neonate
during the period of rapid weight loss and major malabsorption.7, 8 After this
period, healthy babies were born with a birth-weight averaging 0.5 kg less than
their pre-JIB siblings. After a malabsorption operation, a woman may
not be able to rely on adequate absorption of birth control pills, and another
means of contraception must be used. After gastric restrictive or gastric bypass
operations, pregnancy should optimally be deferred until after the period of
rapid weight loss, i.e. 1 year.4 9
Multiple vitamins must be continued during pregnancy after
bariatric surgery. Following gastric restrictive procedures, these may
have to betaken in liquid or chewable form. After restrictive procedures (where
red meat may be taken only with difficulty) increased iron is needed;
after gastric bypass procedures (in which the duodenum - where most iron is
absorbed - is bypassed) increased iron must be taken in pregnancy to allow
adequate absorption in the proximal jejunum. Furthermore, adequate
calcium intake or supplementation should be ensured for mineralization
of the fetal skeleton. 10 Of particular importance is supplemental folic
acid, in order to avoid neural tube abnormalities. 11, 12 Adequate vitamin
B12 and vitamin A should be taken. 10
During normal pregnancy, weight gain of 12 kg is optimal. 10, 13 In
obese individuals, pregnancy is not a time to undertake a major weight-loss
diet; rather, the obese individual should be permitted to gain the usual
pregnancy weight, in order to develop a healthy fetus. However, the obese woman
should be under surveillance so that she does not gain additional excess weight
during pregnancy. Following weight-loss surgery, the gravid woman should be
under surveillance to be sure that she gains weight. If the woman who has had
bariatric surgery does not gain weight or gains very little during pregnancy,
the fetus risks intrauterine growth retardation, fetal abnormality, or a
small-for-dates neonate. 10 As Wittgrove and co-workers emphasize ..., liaison
between the bariatric surgeon and the obstetrician is necessary, so that the
obstetrician understands the nuances and requirements of the pregnant woman who
has had bariatric surgery.
Pregnancy after Bariatric Surgery
Commentary
Mervyn Deitel, MD
Toronto, Canada
Obesity Surgery, 8,1998 Lippincott-Raven Publishers
References
1. Cleland WH, Mendelson CR, Simpson ER. Aromatase activity of
membrane fractions of human adipose tissue stromal cells and adipocytes.
Endocrinology 1983;113: 2155-60.
2. Deitel M, To TB, Stone E et al. Sex hormonal changes accompanying loss of
massive excess weight. Gastroenterol Clin North Am 1987; 16: 511-5.
3. To TB, Deitel M, Stone E et al. Sex hormonal changes after loss of massive
excess weight. Surg Forum 1987; 38: 465-7.
4. Deitel M, Stone E, To TB. Gynecologic-obstetric abnormalities of morbid
obesity, and changes after loss of massive excess weight. In: Deitel M, ed.
Surgery for the Morbidly Obese Patient. Philadephia: Lea & Febiger 1989:
359-64.
5. Deitel M, Stone E, Kassam HA et al. Gynecologicobstetric changes after
loss of massive excess weight following bariatric surgery. J Am Coll Nutr 1988;
7: 147-53.
6. Hey H. Niebuhrlorgensen U. Jejunoileal bypass surgery in obesity:
gynecological and obstetrical aspects. Acta Obstet Gynecol Scand 1981; 60:
135-40.
7. Perlow JH, Morgan MA. Massive matemal obesity and perioperative cesarian
morbidity. Am J ObstetGynecol 1994; 170: 560-5.
8. Ingardia CJ, Fischer JR. Pregnancy after jejunoileal bypass and the SGA
infant. Obstet Gynecol 1978; 52: 215-8.
9. Gurewitsch ED, Smith-Levitin M, Mack J. Pregnancy following gastric bypass
surgery for morbid obesity. Obstet Gynecol 1996; 88: 658-61.
10. Deitel M, Ternamian AM, Noor SS. Intravenous nutrition in obstetrics and
gynecology. J Soc Obstet Gynecol Can 1997; 19: 1171-8.
11. Martin L, Chave GF, Adams MJ et al. Gastric bypass surgery as material
risk factor for neural tube defects. Lancet 1988; 1: 640-1.
12. Mills JL, Conley MR. Folic acid to prevent neural tube defects:
scientific advances and public health issues. Obstet Gynecol 1996; 8: 394-7.
13. Bianco AT, Smilen SW, Davis Y et al. Pregnancy outcome and weight gain
recommendations for the morbidly obese woman. Obstet Gynecol 1998; 91: 97102.
