Impact of thyrotropin receptor antibody levels on fetal development in two successive pregnancies in a woman with Graves' disease.

BACKGROUND: Treatment with radioiodine for Graves' disease regularly increases the level of antithyroid antibodies, and transplacental passage of stimulating thyrotropin receptor antibodies (TRAb) may cause fetal hyperthyroidism. CASE PRESENTATION: A 21-year-old woman with Graves' disease received radioiodine treatment to avoid use of antithyroid drugs in pregnancy. She became pregnant 4 months later and was euthyroid during pregnancy. In gestational week (GW) 33, she was admitted with an increased fetal heart rate of 176-180 beats/min. Fetal echocardiography indicated cardiac decompensation. The neonate had severe hyperthyroidism (free thyroxine >100 pmol/l, nv 12.0-22.0), cardiac insufficiency, insufficient weight gain, goiter and considerably accelerated skeletal age. In the mother and neonate, TRAb was >40 IU/l (nv <1.0), indicating transplacental passage of stimulating antibodies. After delivery, TRAb remained >40 IU/l in the woman, and 18 months later she underwent total thyroidectomy with subsequent decline in TRAb. In her next pregnancy, TRAb fluctuated between 38 and 17 IU/l, and repeated fetal ultrasound showed no goiter or sign of hyperthyroidism. In cord blood, TRAb was 10.9 IU/l, and the neonate had normal thyroid hormone levels. CONCLUSION: This case report illustrates the impact of maternal TRAb level for neonatal outcome in two successive pregnancies.

Preterm infants' timing strategies to optical collisions.

BACKGROUND: A virtual object approaching on a collision course will elicit defensive blinking in infants. Previous research has shown that when precisely timing their blinks, full-term infants shift from using a strategy based on visual angle/angular velocity to a strategy based on time between 22 and 30 weeks of age. AIM: To investigate which timing strategy preterm infants use to determine when to make the defensive blink. METHODS: Eight preterm infants were tested at 26 weeks, corrected for prematurity. For three of these infants, longitudinal data at 22, 26, and 30 weeks were available. The virtual object approached the infants with different constant velocities and constant accelerations. RESULTS: At 26 weeks, three infants blinked when the virtual object's visual angle reached a threshold value causing them to have problems with fast, accelerating approaches. Four infants blinked when the virtual object was a certain time away, allowing them to blink in time on all approach conditions. One infant stood out because he relied on a timing strategy based on angular velocity on all three test sessions, causing him to blink late on a large number of trials even at 30 weeks. CONCLUSION: As good timing is essential for successful interaction with the environment, the inability to switch from a timing strategy that is prone to errors to a strategy that enables successful defensive blinking reflects lack of flexibility to adjust appropriately to local circumstances. This might be an early indication of perceptuo-motor problems that warrants further investigation.