We report a case of a 31-year-old Caucasian woman (weight 50 kg, height 148 cm) with type 1 diabetes diagnosed 27 years ago and Addison’s disease discovered 5 years ago, who had a pregnancy with normal outcome treated with lispro and glargine insulin.
For years, the patient has followed a regimen of multiple daily injections of lispro before meals, NPH at bedtime, and 75 mg/day cortone acetate. Her metabolic control has been constantly altered (April 2002 A1C, 8.4%), and she has had frequent episodes of mild and at times severe hypoglycemia, especially at night. At morning, glycemia was often high. When NPH was changed to insulin glargine, hypoglycemic episodes were drastically reduced, and metabolic control improved (December 2002 A1C, 6.9%).
In August 2003, the patient discovered her pregnancy at the 18th week of gestation (A1C 6.2%, ACTH 6 pg/ml). We informed her that the use of glargine and lispro had not been previously evaluated during pregnancy, but considering that the critical organogenic period had already ended and that metabolic control was good, we suggested that it would be possible to continue use of them throughout pregnancy. The patient gave her written informed consent.
The pregnancy proceeded regularly, and the patient’s weight increased from 50 to 63 kg. At the beginning, the patient took 70 IU/day of insulin (1.4 IU/kg) divided as follows: lispro 42 IU (0.84 IU · kg−1 · day−1) and glargine 28 IU (0.56 IU · kg−1 · day−1). At the end, lispro had to be increased to 88 IU (1.76 IU · kg−1 · day−1), whereas glargine remained unchanged with a total of 116 IU/day (2.32 IU/kg). The patient did not have any important hypoglycemic episodes. A1C and ACTH ranged between 6.2 and 5.9% and 6 and 12 pg/ml, respectively. Use of cortisone was unchanged.
No diabetes complications developed during pregnancy, and blood pressure was always normal. Ultrasound examination showed a normal fetus, smaller for gestational age. Placental flow was normal. A Cesarean section was performed at the 38th week because of the small size of the patient’s pelvis.
A healthy baby girl was born with no malformations: weight 2,150 g (under 10th percentile birth weight), height 44 cm, and Apgar score 9/10. Patient and neonate had no complications during postpartum.
Therefore, in our patient, use of glargine and lispro did not induce any fetal malformations notwithstanding their use from start of pregnancy. It is not known why the fetus was so small for gestational age, since the mother neither smoked nor had any history of drug abuse. Indeed, the mother is small sized, as is her husband, but that is not enough to justify low birth weight.
There are many reports about safe use of lispro in pregnancy, and a recent study demonstrated in vitro that it does not cross the human placenta (1,2). However, little has been written on the use of glargine in pregnancy; one study showed that use after the 3rd month of pregnancy resulted in no fetal malformations (3), whereas two trials report use since the beginning of pregnancy (4,5).
Regarding our patient, it is likely that optimal control of glycemia with this insulin favored a long sought after pregnancy. However, additional studies are needed before stating that glargine is completely safe in pregnancy.
