Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a condition that develops during pregnancy when the body is not able to make enough insulin. GDM affects 2-10% of women during pregnancy.It is important to recognize and treat gestational diabetes as soon as possible to minimize the risk of complications to mother and baby.

2. Table of contents
•Definition
•Risk factors
•Pathophysiology
•Screening
•Complications
•Congenital malformation
•Management
•Contraception

3. Definition
•GDM is defined as carbohydrate intolerance with onset/ first
recognition during the present pregnancy.

4. Risk factors
•Age > 30 years
•Obesity
•Positive family history of diabetes
•H/O giving birth of a baby with a weight >4 kg
•Persistent glycosuria
•Previous stillbirth with pancreatic cell hyperplasia on pregnancy
•Polyhydramnios/ Recurrent vaginal candidiasis on pregnancy
•Unexplained perinatal loss.

5. Pathophysiology
•The hallmark of GDM is increased insulin resistance.
•Placental hormones and increased fat deposits during pregnancy,
both seem to mediate insulin resistance during pregnancy.
•Although cortisoland progesteroneare the main culprits; human
placental lactogen, prolactinand estradiolalso contribute.

6. Screening
DIPSI (Diabetes in pregnancy study group of India) recommends:
•As a pregnant woman walks into antenatal clinic in fasting state, she
has to be given a 75 gm oral glucose load and after 2 hours, a venous
blood sample is collected for estimating plasma glucose.
•A blood sugar > 140 mg/dl is gestational diabetes.
•This screening is recommended between 24-28 weeks of gestation.
Note:
75 gm glucose challenge test has the highest sensitivity for screening
of gestational diabetes mellitus.

7. Complications of diabetes in pregnancy
Maternal Fetal Neonatal
Pre-eclampsia
Pyelonephritis
Polyhydramnios
Preterm labour
Macrosomia
Sudden IUD
Shoulder dystocia
Metabolicdisturbance:
Hypoglycemia/
hypomagnesia/
hyperbilirubinemia/
hypocalcemia
Birth asphyxia
Birth injuries
Transient tachypnea

8. Congenital malformations in diabetes
•The most common congenital anomaly associated with gestational diabetes
are cardiovascular anomalies.
•The most common cardiovascular anomaly in gestational diabetes is VSD.
•The most characteristic cardiovascular anomaly in gestational diabetes is TGA.
•The second most common congenital anomaly associated with gestational
diabetes are neural tube defects (Ex.: anencephaly and spina bifida).
•The lesion characteristically associated with diabetic embryopathy is caudal
regression syndrome/ sacral agenesis.
•Most useful test in 1
st
trimester to identify the risk of fetal malformation in a
fetus of a diabetic mother is measurement of glycosylated Hb.

9. Management of GDM
Target:
Maintaining a mean plasma glucose (MPG) level ~105–110 mg/dL is
desirable for a good fetal outcome.
This is possible if FPG and 2-hour PPBG are ~90 mg/dL and ~120
mg/dL, respectively.

10. Medical Nutrition Therapy (MNT)
•All women with GDM should receive nutritional counselling.
•The meal pattern should provide adequate calories and nutrients to
meet the needs of pregnancy.

11. Initiating Insulin Therapy
•Once diagnosis is made, medical nutritional therapy (MNT) is advised initially
for 2 weeks.
•If MNT fails to achieve control (FBG ~90 mg/dL and/or PPBG ~120 mg/dL),
insulin may be initiated.

12. Continued….
•If GDM is diagnosed in the third trimester; MNT is advised for a week.
Insulin is initiated if MNT fails.
•If 2-hour PPBG > 200 mg/dL at diagnosis, a starting dose of 8 units of
Premixed insulin could be administered straightaway before breakfast
and the dose has to be titrated on follow-up. Along with insulin
therapy, MNT is also advised.
•If PPBG is still not under control—consider using rapid-acting insulin
analogues.

13. Contraception in GDM
•Barrier method of contraceptives is ideal for spacing of births.
•Low dose combined oral pills containing third generation progestins,
are effective and have got minimal effect on carbohydrate metabolism.
Main worry is their effect on vascular disease (thromboembolism and
myocardial infarction).
•Progestin only pill may be an alternative.
•IUCD may be used once diabetes is well controlled.
•Permanent sterilization is considered when family is completed.

14. Thank you