At the end of pregnancy, the child weighed 50 % less than that expected for the gestational age, and the mother weighed 31 % less than before the bariatric surgery. The pregnancy occurred 8 weeks after the malabsorptive intervention, i.e. in the patient’s most catabolic phase. Weight retardation associated with insufficient placenta implantation and development of preeclampsia may be associated with the patient’s obesity at the time of conception, or the child may have been exposed to malnutrition for other reasons.
The expression «weight retardation» is used when a foetus has not reached its weight potential because of genetic or environmental factors. The risk for foetal death is dependant on the gestational length and degree of weight retardation (13). Our patient was followed closely throughout pregnancy, as duodenal switch may cause substantial weight loss the first year after the intervention. In some cases parenteral nutrition and reoperation may be necessary. One may ask whether it was advisable to undergo a pregnancy such a short time after the intervention. Available documention on this issue (7, 10) is not sufficient to advise termination of pregnancy.
In addition to standard vitamin supplementation after surgery, the patient was given extra supplementation of iron and folic acid, which is recommended to all women in the first trimester of pregnancy to prevent neural tube defect in the foetus. Iron is necessary, both for the foetal-placental development and for prevention of anaemia in mother and child. If the foetus is clearly hypoxic in utero; an ultasound examination will show reduced amnion fluid, blood flow changes will be detectable in various foetal vessels and a CTG-examination will show pathological changes. Blood flow was not measured in the uterine artery in our patient, but no other abnormalities were observed.
Hypoalbuminaemia, defined as serum-albumin < 36 g/l, most frequently occurs 6 – 18 months after a duodenal switch procedure (2). The reference range for albumin is about 10 % lower for pregnant women than for others, but nutritional deficiency may also be a cause of hypoalbuminaemia. In our patient the albumin concentration was 29 g/l in gestational week 26. This may be indicative of preeclampsia or protein deficiency.
Can preeclampsia be a cause for weight retardation? According to the Medical Birth Registry in Norway, preeclampsia before Week 34 was the cause of growth retardation in 22 % of children with a low birth weight (13). In preeclampsia, there is an insufficient trophoblast migration in the wall of the spiral arteries. This may damage the spiral arteries by reducing the diameter of the blood vessels, the blood flow and release of cytokines and free radicals. Local infarcts and reduced blood flow may cause deterioration of the foetal nutritional status. The risk is higher in mothers with previous preeclampsia, proteinuria, increased insulin secretion before pregnancy or high BMI at the time of conception.
The Medical Birth Registry reported the HELLP-syndrome in 1.8 of 1 000 pregnancies in Norway in 2006; about 15 – 20 % of the women did not have previous proteinuria or hypertension. The risk of multiorgan failure and death in mothers is decreased with rapid termination of pregnancy or labor within a short time (quick birth). Preeclampsia had not been confirmed before our patient developed the HELLP syndrome. Placenta findings indicate insufficient implantation. This is observed both in serious preeclampsia and weight retardation in the foetus. Hypoalbuminaemia may also be involved.
A number of professional groups were involved in treatment of the patient; i.e. general practitioner, surgeon, specialist in internal medicine, gynecologist, anaesthesist, paediatrician and midwife. Crossdisciplinary cooperation is a prerequisite for successful bariatric surgery. Routines differ between regions (according to telephone discussions with other treatment centres) and no guidelines are available for follow-up of pregnant women after bariatric surgery.
It has been suggested to limit the number of malabsorptive interventions in fertile women to reduce the risk of nutritional deficiency during pregnancy (11). Fertile women who undergo malabsorptive surgery should be recommended (in writing) to avoid pregnancy in the first 12 months after the operation and they should be informed that fertility may increase as a result of weight loss. Before the operation, they should also be advised about contraception. Hormone-releasing intrauterine devices may be favourable options; they reduce the amount of bleeding, are not associated with increased weight or an increased risk of venous thrombosis and their safety does not depend on the woman’s weight (14).
Patients who become pregnant should be referred to a gynecologist for ultrasound control. Foetal growth should be monitored monthly from week 22 in patients who become pregnant shortly after the operation and in patients who have undergone malabsorptive surgery. Serum albumin levels should be monitored regularly if the operation was performed less than one year before start of pregnancy. Additional iron and folate supplements are often necessary. Vitamin B12 supplements should be given after gastric bypass and fat-soluble vitamin levels should be monitored after malabsorptive interventions.