***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Loratadine is a second-generation histamine H(1)-receptor antagonist , used in the treatment of allergic conditions . No prospect i ve controlled trials on loratadine in human pregnancy have been published to date . OBJECTIVE To determine whether the use of loratadine or other antihistamines ( OAH ) is associated with an increased risk of major anomalies . METHODS Callers who were counseled by the Israeli Teratogen Information Service in regard to loratadine or OAH exposure during pregnancy were prospect ively collected and followed up . Pregnancy outcome was compared among three exposure groups :  loratadine , OAH  , and a  control group of patients who were counseled for nonteratogenic exposure , nonteratogenic controls ( NTC ) .  The OAH included astemizole , chlorpheniramine , terfenadine , hydroxyzine , promethazine , and dimetindene . RESULTS We followed up 210 pregnancies exposed to loratadine ( 77.9 % in the first trimester ) and 267 pregnancies exposed to OAH ( 64.6 % in the first trimester ) and compared pregnancy outcome with that of 929 NTC . The rate of congenital anomalies did not differ among the groups [ loratadine : 4/175 ( 2.3 % ) , OAH : 10/247 ( 4.0 % ) , NTC : 25/844 ( 3.0 % ) , P = .553 , relative risk ( RR ) , 0.77 ; 95 % confidence interval ( CI ) , 0.27 to 2.19 , ( loratadine vs NTC ) ; RR , 0.56 ; 95 % CI , 0.18 to 1.77 , ( loratadine vs OAH ) ] . The rate did not differ between those exposed to antihistamines in the first trimester and the control patients [ loratadine : 1/126 ( 0.8 % ) , OAH : 7/146 ( 4.8 % ) , NTC : 25/844 ( 3.0 % ) , P = .152 , RR , 0.27 ; 95 % CI , 0.04 to 1.94 , ( loratadine vs NTC ) ; RR , 0.17 ; 95 % CI , 0.02 to 1.33 , ( loratadine vs OAH ) ] . CONCLUSIONS This study on the use of loratadine in human pregnancy suggests that this agent does not represent a major teratogenic risk . The study was powered to find a 3-fold increase in the overall rate of major anomalies OBJECTIVE : This study compares pyridoxine – metoclopramide combination therapy to prochlorperazine and promethazine monotherapies in the outpatient treatment of nausea and vomiting in pregnancy . STUDY DESIGN : In total , 174 first trimester , singleton pregnancies were evaluated for nausea and vomiting . Patients were prospect ively r and omized into three treatment groups : pyridoxine – metoclopramide , prochlorperazine , or promethazine . Prior to , and on the third day , patients recorded their subjective responses to the given treatment and their number of emesis episodes . The three treatment groups were compared for therapy response . RESULTS : There were no differences in the number of emesis episodes prior to treatment . Both subjective and objective responses to treatment differed among the three groups when comparing the combination therapy to the monotherapies ( p<0.05 ) . CONCLUSION : Combination therapy with pyridoxine and metoclopramide appears to be superior to either monotherapy in the treatment of nausea and vomiting in pregnancy Abstract In a prospect i ve study , data on whether an antinauseant drug was prescribed in the first 12 weeks of pregnancy were available for 4,277 gravidas—330 fell into the meclizine-cyclizine group , 473 were prescribed “ other ” antinauseant drugs , and for the remainder no antinauseant drugs were prescribed . The abortion and perinatal mortality rates and the number per 100 infants of nontrivial and of severe anomalies for the gravidas in the meclizine-cyclizine group compared very favorably with the other two groups . Gravidas for whom no antinauseant drugs were prescribed suffered much higher early fetal death rates than those for whom antinauseant drugs were prescribed . When the latter were subdivided into those who did and did not suffer nausea and vomiting early in pregnancy , it was found that gravidas who did not complain of nausea and vomiting in early pregnancy suffered abortion rates three times as high as gravidas who complained of nausea and vomiting In some countries , including Sweden , no risk is considered to exist with the use of meclozine for nausea and vomiting in pregnancy ( NVP ) , but in other countries warnings against use during pregnancy are given . Rat tests indicate a teratogenic risk and published epidemiological studies are of restricted size . Delivery outcome was studied in 16,536 women who reported the use of meclozine in early pregnancy and was compared with all 540,660 women who gave birth . Information on drug usage was obtained prospect ively in early pregnancy . Risk factors for using meclozine were young maternal age , to have had a previous child , not to smoke , to have a low body mass index . The use of some other drugs ( antihypertensives , thyroxine , anticonvulsants ) decreased the use of meclozine .  Maternal diagnoses of preeclampsia or diabetes were less frequent when the woman had used meclozine . The twinning rate was increased and the sex distribution of the infants low ( female excess ) . Preterm birth , low birth weight , short body length , and small head circumference occurred at a reduced rate after meclozine use , notably for boys . Also the rate of congenital malformations was reduced . If anything , delivery outcome is better than expected when the mother used meclozine . These beneficial effects are probably secondary to NVP .  Meclozine can apparently be used without risk at this condition In a large , prospect i ve , observational study of pregnancy and child development , the  antinauseant drugs  prescribed to gravides for nausea and vomiting in the first 84 days of pregnancy were evaluated for their teratogenic potential . The severe congenital anomaly rates per 100 liveborn children and ther perinatal death rates of this group did not differ from the rates of the group with untreated nausea and vomiting . There was no indication that the phenothiazine derivatives , specifically the prochlorperazine derivative , as well as meclizine , cylizine , and Bendectin were associated with teratogenicity . The trimethobenzamide drug gave a slight suggestion of an excess of severe congenital anomalies During the mid-1960s , 22 977 pregnant women in Scotl and and Engl and were followed up prospect ively for the incidence of malformations in their infants evident at birth or within six weeks . During the first 13 weeks of gestation 620 of these women had been prescribed Debendox ( dicyclomine-doxylamine-pyridoxine ) and 743 other women agents other than Debendox containing pyridoxine . Of the 620 women given Debendox , 589 ( 95 % ) had a normal outcome of pregnancy , 8 ( 13 % ) delivered a malformed infant , and 23 ( 3.7 % ) had other outcomes . Of the 22 357 women who were given Debendox , 445 ( 2.0 % ) produced infants with malformation ; and the rates for all abnormal outcomes among women given Debendox and those not given the drug were 5.0 % and 5.4 % respectively . These results support the hypothesis that Debendox is not teratogenic Since the introduction of nonsedating selective H1 antagonists , they have been largely used by women of reproductive age for the treatment of seasonal allergic rhinitis , conjunctivitis , chronic urticaria , and other allergic conditions . However , because of tack of human studies on the reproductive safety of these compounds , their manufacturers either can not support their use in pregnancy , through the product monographs , 1 or label them as relatively safe even when no data exist to support such statements . The issue of documenting pregnancy outcome after exposure to new drugs is even more complex if one considers that over 50 % of all pregnancies are unplanned , and therefore it may not be sufficient to advise women " not to use a compound in pregnancy . " Astemizole is a potent long-acting selective H1 blocker antihistamine , which does not produce the typical central nervous system depression and drowsiness . In animal studies , doses that were 200to 800-fold the recommended human dose per kilogram did not induce teratogenic effects ? We report on the first prospect i ve , controlled , observational study of women who took astemizole during the first trimester of pregnancy and their offspring Abstract . In a prospect i ve study of anti‐emetic drug use during 6 376 pregnancies , the previously demonstrated negative correlation between the use of such drugs and  miscarriage  was confirmed . It is probably completely due to less frequent and possibly less severe morning sickness complaints in pregnancies ending with a miscarriage . A slight positive correlation is found between the use of anti‐emetics and infant malformation . A detailed analysis showed that this was mainly due to a high incidence of drug use ( mainly promethazine ) among women giving birth to infants with congenital dislocation of the hip . The probable indirect relationship is discussed BACKGROUND Women in their childbearing years often require drug therapy for allergic conditions . Loratadine , a newer nonsedating antihistamine , is often used because of its preferred side effect profile . To date no published data exist on the safety of loratadine use in pregnancy . OBJECTIVE We sought to determine whether the use of loratadine in the first trimester of pregnancy was associated with an increased risk for major malformations . Secondary outcomes included rates of miscarriage , birth weights , and gestational age at delivery . METHODS All women were prospect ively enrolled from 4 participating centers . Detailed maternal medical history and drug exposures were collected at intake , whereas pregnancy complications and outcomes were collected at follow-up . A group of unexposed control subjects were recruited and followed up in a similar manner . RESULTS This report includes follow-up on 161 loratadine exposed pregnancies and an equal number of unexposed control subjects . Maternal characteristics ( age , pregnancy history , alcohol consumption , and smoking habits ) were not different between the 2 groups . There were 5 malformations observed in the exposed group and 6 in the control group , which was not significantly different ( P = .9 ) Similarly , the live birth rate , gestational age at delivery , and birth weights were not different between the 2 groups . CONCLUSION These results suggest that loratadine use in pregnancy is not associated with a large risk for major malformations . Further studies are warranted to confirm these findings and to increase study power OBJECTIVE To assess the safety of cetirizine during pregnancy . STUDY DESIGN A prospect i ve observational cohort study with data of the Berlin teratology information center from 1992 until 2006 . Pregnancy outcome was compared between a cohort of pregnant women exposed to cetirizine during the first trimester ( n=196 ) and a control group not exposed to potential teratogens ( n=1686 ) . RESULTS Major birth defects were not more common in the study group than in the control group ( OR 1.07 ; CI 0.21 - 3.59 ) . We also compared the crude rate of spontaneous abortions ( OR 0.97 ; CI 0.54 - 1.65 ) , of preterm deliveries ( OR 0.76 ; CI 0.35 - 1.5 ) , and the birth weight of term newborns ( p=0.13 ) . CONCLUSIONS This prospect i ve observational study on cetirizine in pregnancy suggests that the use of cetirizine is relatively safe during the first trimester BACKGROUND Case-control studies have suggested that the nausea and vomiting of pregnancy ( NVP ) may have a protective effect against specific malformations . These suggestions have been interpreted as if the lack of NVP may put mothers at an increased teratogenic risk . METHODS A prospect i ve , cohort-controlled study was done comparing pregnancy outcome in women not experiencing NVP with those experiencing NVP at two levels of clinical severity . Women who called the Motherisk program about first-trimester exposure to drugs and who had not experienced NVP were included as the study group . The  NVP Healthline enrolled two control groups of women with NVP treated with a doxylamine-pyridoxine combination for morning sickness . These women were exposed during the first trimester of gestation to either higher than the st and ard dose ( 5 - 12 tablets/day ) or a st and ard dose ( 1 - 4 tablets/day ) of doxylamine-pyridoxine . The women in all three groups were followed up four to six months after the expected date of birth to ascertain pregnancy outcomes and child health . RESULTS There were no major malformations among offspring of 130 women not experiencing NVP . There were two major malformations among 246 women experiencing NVP . The two control groups of women with NVP had similar distributions of gestational ages , birth rates , as well as rates of miscarriages and stillbirths , as in the no-NVP group . CONCLUSIONS This study did not show an association between lack of NVP and an increase in the overall rates of major malformations BACKGROUND Terfenadine is a selective , nons 
    Output:
    
Conclusions Based on our meta-analyses , which included a large number of studies , H1 antihistamines are not associated with an increased risk of major malformation or other adverse fetal outcomes .
This study provides important information to both pregnant women and their healthcare providers regarding the safety and risk of H1 antihistamine use during this sensitive time