Management of Pregestational DM in FIRST TRIMESTER
Pregestational DM History:
• Classification: type 1 or 2
• Insulin or oral hypoglycemic?
• Complications associated in the pregnancies before?
• Idea about glycemic control: if she has self-monitoring paper.
Pregestational DM Routine investigations:
CBC, bl group & Rh, serology (HBV, rubella, syphilis) & urine (asymptomatic bacteriuria).
Hb A1C: it reflects the glycemic control over the prior 8-12 wk& thus assists in counseling her regarding the risks of miscarriage, CFMF & preeclampsia. The American Diabetes Association (ADA) recommends aiming for an A1c<6.5%.
Assessment of comorbidities: baseline renal function, thyroid function tests (thyroid dysfunction is common with type 1 DM), eye examination by an ophthalmologist to detect retinopathy.
US: to document viability, as the rate of miscarriage is high in women with diabetes especially those with poor glycemic control.
Management of first trimester Pregestational DM General Principles:
• Explain to the mother the importance of self-monitoring of blood glucose, diet therapy, medication & exercise.
• Target blood glucose values acc. to The ACOG & the American Diabetes Association (ADA):
…Fasting ≤95 mg/dL.
… Pre-prandial ≤100 mg/dl.
… 1-hr postprandial ≤140 mg/dl.
… 2-hr postprandial ≤120 mg/dl.
• Explain to the patients with a markedly elevated A1C value of the increased risk of CFMF especially NTD & cardiac defects.
• For those with type 1 & 2 DM, begin aspirin 81 mg/day after 12 wk to decrease the risk of preeclampsia (we can start earlier).
• The ACOG recommends preconception & 1st▲ supplementation with 4 mg of folic acid dt.the risk of NTD.
• Refer her to endocrinologist, dietician & diabetic educator to help her control her bl. Sugar.
• Extra visits can be used to review monitored blood glucose values, results from the ophthalmologic & laboratory examination (e.g. renal function, A1C, thyroid function).
• If a woman is both obese & diabetic, the clinician should be mindful of the potential morbidities of both conditions.
Type 1 DM Dosing:
• Multiple daily injection regimen (3-4) in pregnant women is preferred especially in women with type 1 DM.
• Insulin requirements during the 1st trimester are similar to those prior to pregnancy in women with type 1 DM.
• Dosing is continually adjusted based on self-monitoring of blood glucose & A1C values.
• The average insulin requirements in pregnant women with type 1 diabetes are:
… 1st▲ → 0.7 U/kg.
… 13-28 wk → 0.8 U/kg.
… 29-34 wk → 0.9 U/kg.
… 35 wk till term → 1 U/kg.
• Approximately 50% of the total insulin dose is administered as a rapid acting insulin (eg, Humalog or NovoRapid) before each meal & the other 50% is administered as an intermediate insulin (NPH) twice daily or long-acting insulin (Lantus or Levemir) once or twice daily.
• For most pregnant women, each premeal dose is approximately 0.15 times their pregnant weight in kg & the basal dose (intermediate or long-acting insulin) is calculated as 0.45 times the patient’s weight in kg.
• As an example, an 80 kg pregnant woman with diabetes would take 12 units (80 x 0.15) of Humalog or NovoRapid before each meal & 18 units (80 x 0.45 /2) of NPH or Levemir twice daily or 36 unit (80 x 0.45) of Lantus once daily. The first Levemir dose is given before breakfast & the second dose is given either before dinner with a rapid-acting insulin or at bedtime, whichever works best for avoiding nocturnal hypoglycemia. Total dose in the example above is (12 x 3)+(18 x 2)= 36 (50%)+36 (50%)=72 Unit= average insulin dose at 3rd trimester (80 x 0.9).
Type 2 DM Dosing:
• For women with excellent glycemic control on an oral anti-hyperglycemic drug such as metformin at conception, maintaining euglycemia during organogenesis is critical & more important than switching to insulin.
• Metformin can be continued safely & effectively as the transition to insulin is initiated & until the dose of injected insulin is sufficient to achieve metabolic control.
• Some women with excellent metabolic control on metformin may choose to continue this therapy & take supplemental insulin later in pregnancy (if needed).
• We can use the same calculations above, but patient may need more insulin in type 2 DM dt.the insulin resistance is very high in type 2.
Management of Pregestational DM in SECOND TRIMESTER
Management of second trimester Pregestational DM General_Principles:
• As above.
• Visits every 2-4 wk through the 2nd▲, but more frequently if complications arise or
glycemic control is suboptimal.
Screening for CFMF: full anomaly scan (U/S) is done at 18-20 wk& focus on NTD &
cardiac anatomy.
Management of Pregestational DM in THIRD TRIMESTER
Management of third trimester Pregestational DM General Principles:
• Visits every 1-2 wk until 36 wk, then weekly until delivery.
• Close monitoring of maternal blood glucose levels.
• Monitoring FWB to minimize the risk of IUFD.
• Evaluation for macrosomia or IUGR: U/S at 28-32 wk to assess fetal growth & repeat at 3-4 wk intervals.
• Evaluation for obstetrical or medical complications necessitating premature delivery.
Antepartum Monitoring: the ACOG recommend using fetal movement counting, biophysical profile &/or NST weekly starting at 32-34 wk then increase the frequency of testing to twice weekly from 36 wk until delivery.
Umbilical artery Doppler may be required to assess for IUGR.
– If non-reassuring fetal testing dt.a reversible problem such as hyperglycemia or DKA, it is advisable to resuscitate the fetus in utero by treating the medical disorder (pathological FHR patterns will often revert to normal when the mother’s metabolic status is corrected).
– Do the last U/S at 38 wk to estimate the fetal weight & decide the plan of delivery.
Administration of betamethasone if preterm birth is anticipated or planned (may cause
transient hyperglycemia).
Management of Pregestational DM in DELIVERY
– When emergency early delivery is indicated, it is important to remember that RDS is more likely to develop than in infants of women without diabetes delivered early.
– Woman with good glycemic control & no vascular disease (as nephropathy or retinopathy), delivery at 39 wk is indicated if favorable cervix.
– Woman with good glycemic control, no vascular disease, normal fetal growth, reassuring fetal surveillance & no history of IUFD, but unfavorable cervix, induction of labor can be safely delayed until 40 wk.
– Woman with pregestational diabetes & “vascular disease”, delivery at 37-39 wk is appropriate.
– Woman with pregestational diabetes & “poor glycemic control”, delivery at 34-37 wk following an amniocentesis for documenting fetal lung maturity can be considered.
– In cases with repeated unexplained IUFD, terminate 1-2 wk earlier.
– According to ACOG, prophylactic CS can be done to prevent brachial plexus injury dt.shoulder dystocia if macrosomia.
– Maternal diabetes is not a contraindication to a trial of labor after a previous CS (VBAC); however, the success rate may be lower than in women without diabetes.
-Peripartum maintenance of maternal euglycemia is essential.
– Insulin requirements: drop sharply after delivery & should be recalculated at this time based on sliding scale.
– NICU consultation for the baby after delivery dt.the possible morbidities after delivery