Hypertension, diabetes and obesity - what should you know?

Hypertension, diabetes and obesity – as first-time mothers age, the risks and prevalence of these conditions also increase. During pregnancy, they are a particular challenge. Different approaches than usual are indicated.

Arterial hypertension, diabetes mellitus and obesity – internal diseases in the focus of prenatal care. As first-time mothers age, the risks and prevalence of these conditions also increase. Although they are part of an internist’s or general practitioner’s daily routine, they are particularly challenging during pregnancy and require different therapies or approaches than usual.

Obesity – an independent risk factor (case 1)

Within the last 40 years, the proportion of obese women worldwide has increased sharply. In Switzerland, it doubled from 1992 to 2012 (from 5% to 9%), and overall the proportion of obese and overweight women was 32% in 2012 (www.admin.ch).

Obesity is an important risk factor in pregnancy, and it is important to (know) and treat the specific problems. The interdisciplinary approach is of great importance here and basic knowledge of e.g. bariatric surgery is an advantage.

Obesity (BMI >30 ^kg/m2) is associated with a number of risks. This begins in early pregnancy with more frequent miscarriages. More congenital anomalies are seen and more complications during pregnancy such as pregnancy-associated hypertension, higher risk of preeclampsia, and development of gestational diabetes [1]. During labor, there is a higher risk of shoulder dystocia as a possible consequence of macrosomia, there are more sectios and discharges before the 37th SSW (due to pregnancy complications), and there is also an increased risk of IUFT. Postpartum wound healing disorders, postpartum depression, and thrombosis are more common [2].

Counseling obese women – what to look for during prenatal care?

Certainly, weight loss is useful before planning a pregnancy. Bariatric surgery should be discussed as a possible therapy, but it should not be performed because of a planned pregnancy, but according to the common indications. According to recommendations, after bariatric surgery, two to three years should be waited until planning pregnancy to achieve the most optimal neonatal outcome [3]. In most cases nowadays, laparoscopic gastric bypass surgery is performed, i.e. a malabsorptive variant. These pregnant women have an increased risk of deficiency development in the sense of “small for gestational age” fetuses (SGA) and must be regularly monitored both sonographically and for possible malnutrition on the part of the mother (routine small blood count, ferritin, vitamin B12, calcium, and vitamin D3 in each trimester; in the case of deficiency or necessary substitution, monthly checks are indicated) [4]. When performing the oral glucose tolerance test (oGTT), caution must be exercised in these women; in 50%, dumping syndrome occurs and alternative screening must be used (fasting blood glucose and postprandial BG during one week or HbA1c). In women with restrictive bariatric surgery (e.g., gastric banding or gastric tube), a normal oGTT may be performed. When abdominal pain occurs in women after gastric bypass surgery, the indication for diagnostic laparoscopy should be generous because of possible internal hernia (case 1).

The recommended weight gain during pregnancy depends on the baseline BMI. For overweight (BMI 25-29.9 ^kg/m2), an increase of 7-11.5 kg is adequate; for obesity (BMI >29.9 ^kg/m2), an increase of 7-9 kg is adequate.

Hypertensive disorders – risk of preeclampsia (case 2).

Hypertensive disease in pregnancy occurs in 4-7% of cases and is a major cause of maternal and fetal morbidity and mortality. Therefore, a normal pregnancy check always includes the measurement of blood pressure (BP). Normally, pregnant women tend to be hypotensive, and there are women with preexisting arterial hypertension who have normotensive BP values in pregnancy. We distinguish pregnancy-induced hypertension (hypertension without proteinuria after the 20th SSW) from chronic, that is, preexisting hypertension. In both cases, the risk of preeclampsia is very high (up to 40% or fourfold increase). It is important to start antihypertensive therapy only from BP values of systolic 150-160 mmHg and diastolic 100-110 mmHg (tab. 1). Since this is a demand hypertension, lowering BP too quickly or too much should be avoided if possible, otherwise the care of the child will be jeopardized. Lowering BP does not affect the development of preeclampsia, i.e., we protect the woman, but the risk for preeclampsia remains. In such cases, close monitoring is indicated, and sometimes hospitalization is necessary, with induction of labor if necessary. If severe preeclampsia is manifest, it should be performed with i.v. magnesium under convulsive prophylaxis [5,6]. In the MAGPIE study, prophylaxis was shown to reduce the risk of seizures by 50% [7]. In subsequent pregnancies, therapy with Aspirin ^Cardio® 100 mg (12th-35th SSW) reduces the recurrence risk of preeclampsia (approximately 8%) by half [8]. Women with preeclampsia have an increased risk of developing cardiovascular disease later in life. An annual check of blood pressure, lipids, blood glucose, and BMI is advisable (Table 2) [9].

Diabetes mellitus – look for it, recognize it, treat it (case 3)

As early as the 1950s, the Danish epidemiologist Pedersen postulated the relationship between maternal hyperglycemia and fetal hyperinsulinemia. The maternal oversupply of sugar is transferred to the fetus, which produces large amounts of insulin in response and becomes macrosomic as a result. Postpartum, the maternal sugar supply then falls away and the newborn develops hypoglycemia.

In the large-scale HAPO study of 2008, this hypothesis was confirmed: Increased glucose concentration has a strong association with fetal birth weight [10]. From these findings, the International Association of Diabetes and Pregnancy Study Group (IADPSG) has established cut-off values and recommended global screening in all pregnant women [11,12].

In Switzerland, approximately 11% of pregnant women have gestational diabetes (GDM). A distinction must be made between diabetes that occurs during pregnancy (transient diabetes in the second half of pregnancy with spontaneous normalization postpartum), type 2 diabetes mellitus that is first detected during pregnancy, and preexisting type 1 or 2 diabetes mellitus.

Pregnancies with diabetes mellitus type 1 or 2 are high-risk pregnancies and require close and interdisciplinary management by specialists (growth controls with Doppler sonography). In contrast, if gestational diabetes is well controlled, regular pregnancy checks can be performed (Table 3).

Every pregnant woman is screened between the 24th and 28th SSW using an oral glucose tolerance test (oGTT) (Table 4) [13,14].

Therapy for GDM consists of nutritional counseling and instruction in blood glucose self-monitoring. If dietary therapy does not improve blood glucose levels within four to seven days or if target glucose levels are exceeded in more than 10% of all measurements, insulin therapy is indicated. This is necessary in about 25% of pregnant women. Although insulin therapy remains the gold standard, there are recent data that also describe the possibility of using metformin (start 2× 500 mg/d, increase to 2× 1000 mg/d possible). However, this is an “off-label” application where long-term data are not yet available [15,16].

Physiological insulin resistance

In pregnancy, maternal insulin resistance is a normal phenomenon that begins in the second trimester and peaks in the third trimester. It is the result of increased placental secretion of diabetogenic hormones. Gestational diabetes develops when pancreatic function is insufficient, i.e., unable to overcome insulin resistance.

This also explains why women with gestational diabetes have an increased risk of developing diabetes mellitus later in life (50-70%): Pancreatic function has virtually failed the “stress test” during pregnancy. In addition, it is also clear that placental insufficiency must be ruled out when insulin requirements decrease during pregnancy: The placenta is generally insufficient and thereby also secretes fewer diabetogenic hormones.

It is important to look for diabetes, recognize it and treat it properly, because the effects of diabetes during pregnancy are manifold and affect both mother and child. An increased risk of preeclampsia or infection is observed in the pregnant woman, and the sectiorate also increases. Fetal intrauterine fetal deaths, malformations (in poorly controlled DM type 1 or 2), growth retardation or macrosomia, and preterm birth are observed more frequently. Postnatal neonatal hypoglycemia or hyperbilirubinemia may occur.

The risk of recurrence of GDM in the next pregnancy is 50-60%.

Take-Home Messages

Obesity is an important risk factor in pregnancy.
For optimal neonatal outcome, wait two to three years after bariatric surgery to plan for pregnancy. Pregnant women after laparoscopic gastric bypass surgery are at increased risk for deficiency development (“small for gestational age” fetuses, SGA) and require follow-up. Interdisciplinary and close-meshed care is important.
Pre-existing hypertension poses a risk for preeclampsia. However, corrected BP does not change the clinical picture of preeclampsia.
Thresholds for therapy initiation are 150-160/100-110 mmHg.
Demand hypertension: avoid too rapid or severe BP lowering!
There is an association between maternal blood glucose and fetal outcome. Diabetes should therefore be sought, recognized and treated. Insulin therapy remains the gold standard.

Literature:

Farren M, et al: The interplay between maternal obesity and gestational diabetes mellitus. J Perinat Med 2015; 43(3): 311-317.
Weiss JL, et al: Obesity, obstetric complications and cesarean delivery rate – a population-based screening study. Am J Obstet Gynaecol 2004; 190: 1091-1097.
Parent B, et al: Bariatric Surgery in Women of Childbearing Age, Timing Between an Operation and Birth, and Associated Perinatal Complications. JAMA Surg 2017; 152(2): 1-8.
Jans G, et al: Maternal micronutrient deficiencies and related adverse neonatal outcomes after bariatric surgery: a systematic review. Adv Nutr 2015 Jul 15; 6(4): 420-429.
Salinger DH, et al: Magnesium sulphate for prevention of eclampsia: are intramuscular and intravenous regimens equivalent? A population pharmacokinetic study. BJOG 2013 Jun; 120(7): 894-900.
Keepanasseril A, et al: Prophylactic magnesium sulfate in prevention of eclampsia in women with severe preeclampsia: randomised controlled trial (PIPES trial). J Obstet Gynaecol 2018 Apr; 38(3): 305-309.
Simon J, et al: Cost-effectiveness of prophylactic magnesium sulphate for 9996 women with pre-eclampsia from 33 countries: economic evaluation of the Magpie Trial. BJOG 2006 Feb; 113(2): 144-151.
Bujold E, et al: Prevention of preeclampsia and intrauterine growth restriction with aspirin started in early pregnancy: a meta-analysis. Obstet Gynecol 2010; 116: 402-414.
The American College of Obstetricians and Gynecologists: Hypertension in Pregnancy. 2013.
The HAPO Study Cooperative Research Group: Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study: associations with neonatal anthropometrics. Diabetes 2009 Feb; 58(2): 453-459.
International Association of Diabetes and Pregnancy Study Groups Consensus Panel: International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycemia in pregnancy. Diabetes Care 2010; 33: 676-682.
Legardeur H, et al: Dépistage du diabète gestationnel: vers un nouveau consensus? Gynécologie Obstétrique & Fertilité 2011; 39: 174-179.
SGGG Expert Letter 2011; no. 37.
Surbeck D: Gestational diabetes: finally a uniform screening strategy! Switzerland Med Forum 2011; 11(51-52): 965-966.
Balsells M, et al: Glibenclamide, metformin an insulin for the treatment of gestational diabetes: a systematic review and meta-analysis. BMJ 2015; 350: h102.
Gross J, et al: Gestational diabetes: diagnostic and therapeutic approach. Switzerland Med Forum 2017; 17(46): 1009-1014.