Transplacental Hemophilia a and Prophylactic Treatment with Recombinant FVIIa in the Newborn Period
Authors: Aytac Selin , Celik Tolga , Yigit Sule , Gumruk Fatma 
Published: October 2019

Abstract
Acquired hemophilia due to inhibitor antibodies is a rare entity during childhood period. Moreover, transplacental hemophilia during the newborn period as a result of maternal IgG antibodies (inhibitors) which may cross the placenta into the foetal circulation is very rare and may cause life- threathening neonatal hemorrhages. The occurence of acquired hemophilia during or after delivery may lead bleeding tendencies in both the mother and baby.
Here, we want to decribe a newborn baby who delivered from a mother with an initial diagnosis of acquired Hemophilia A and succesfully treated with a prohylactic rFVIIa.
Case : A 27 years old women who was diagnosed with an acquired hemophilia A after her first delivery was admitted to our hospital for the second delivery.Her pregnancies were 15 months apart. Her FVIII level was found to be low (<1%) with a very high titer (>100NBU) inhibitor.She was treated with rFVIIa before C/S by adult hematologist and after giving a birth to a term boy without any bleeding complication, newborn baby was referred to our department because of having low FVIII level (0.3 %) with high titer inhibitor(320 NBU) and an abnormal aPTT mixing test on the first day of life. Cranial and abdominal USG was found to be normal and despite having no bleeding event we decide to give IVIG treatment due to very high titer of inhibitor level. On the 3rd day of life some blood in the stool was detected however there is no decrease in the Hb level. Prophylactic rFVIIa with a dose of 90µg/kg/daily was given during the next 4 weeks and inhibitor level was checked regulary. His inhibitor level was decraesed gradually on the first week 256NBU , second week 51 NBU and 4th week 2NBU with a FVIII level 2.7% and propylactic treatment was stopped on the 5th week of life. Although we did not able to detect inhibitor antibodies by trying to do aptt mixing test in the breastmilk, his mother did not have enough breatmilk and baby was supported by infant formula as well.
There was a few numbers of cases with neonatal acquired hemophilia due to transplacental transfer of autoantibodies reported in the literature . It was reported that most inhibitors spntaneously disappear over a median 30 months after delivery and FVIII inhibitors are rarely present during labor and delivery in the next pregnancy. However, in our case 15 months after the first pregnacy he was delivered. The outcome of the transplasental acquired hemophilia cases reported in the literature was favorable with a resolution after a median of 3 months (range 0.2-3 months) despite one of them experienced intracranial hemorrhage.. Although peak inhibitor titer was reported to be 150BUin the literature, in our case it was the higher than the reported level (320NBU). However despite a very high peak inhibitor titer, we can speculate that due to limited intake of breastmilk which may also contain inhibitor antibodies may ameoliorate the prompt decrase of inhibitor antibodies. rFVIIa is safe and protect our patient from life-threatening bleeding events without any complication.

Disclosures
No relevant conflicts of interest to declare.