How Many Embryos should be Transferred? The Relevance of Parity and Obstetric History.

BACKGROUND Fertility treatments are responsible for the rise in high order pregnancies in recent decades and their associated complications. Reducing the number of embryos returned to the uterus will reduce the rate of high order pregnancies. OBJECTIVES To explore whether obstetric history and parity have a role in the clinician's decision making regarding the number of embryos transferred to the uterus during in vitro fertilization (IVF). METHODS In a retrospective study for the period August 2005 to March 2012, data of twin deliveries > 24 weeks were collected, including parity, mode of conception (IVF vs. spontaneous), gestational age at delivery, preeclampsia, birth weight, admission to the neonatal intensive care unit (NICU), and Apgar scores. RESULTS A total of 1651 twin deliveries > 24 weeks were record- ed, of which 959 (58%) were at term (> 37 weeks). The early preterm delivery (PTD) rate (< 32 weeks) was significantly lower with increased parity (12.6%, 8.5%, and 5.6%, in women with 0, 1, and ≥ 2 previous term deliveries, respectively). Risks for PTD (< 37 weeks), preeclampsia and NICU admission were significantly higher in primiparous women compared to those who had one or more previous term deliveries. Primiparity and preeclampsia, but not IVF, were significant risk factors for PTD. CONCLUSIONS The risk for PTD in twin pregnancies is significantly lower in women who had a previous term delivery and decreases further after two or more previous term deliveries. This finding should be considered when deciding on the number of embryos to be transferred in IV.

[1]  H. Jones,et al.  Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction. , 2013, Human reproduction.

[2]  O. Ozturk,et al.  Number of embryos for transfer following in vitro fertilisation or intra-cytoplasmic sperm injection. , 2013, The Cochrane database of systematic reviews.

[3]  L. Warner,et al.  Elective single embryo transfer trends and predictors of a good perinatal outcome--United States, 1999 to 2010. , 2013, Fertility and sterility.

[4]  U. Gorkem,et al.  The impact of single embryo transfer policy on pregnancy outcomes after legislative change , 2013, Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology.

[5]  M. Velez,et al.  Rapid policy change to single-embryo transfer while maintaining pregnancy rates per initiated cycle. , 2013, Reproductive biomedicine online.

[6]  N. Gleicher,et al.  Mistaken advocacy against twin pregnancies following IVF , 2013, Journal of Assisted Reproduction and Genetics.

[7]  A. Thurin-Kjellberg,et al.  Neonatal and maternal outcomes comparing women undergoing two in vitro fertilization (IVF) singleton pregnancies and women undergoing one IVF twin pregnancy. , 2013, Fertility and sterility.

[8]  J. Petrozzino,et al.  Obligatory versus elective single embryo transfer in in vitro fertilization. A population-based analysis of data from the U.K. Human Fertilisation and Embryology Authority. , 2013, The Journal of reproductive medicine.

[9]  T. J. Mathews,et al.  Infant mortality statistics from the 2009 period linked birth/infant death data set. , 2013, National vital statistics reports : from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System.

[10]  Criteria for number of embryos to transfer: a committee opinion. , 2013, Fertility and sterility.

[11]  Ks Joseph,et al.  Temporal trends in the frequency of twins and higher-order multiple births in Canada and the United States , 2012, BMC Pregnancy and Childbirth.

[12]  I. Szymusik,et al.  IVF versus spontaneous twin pregnancies – which are at higher risk of complications? , 2012, The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians.

[13]  I. Usta,et al.  Effect of parity on maternal and neonatal outcomes in twin gestations , 2006, Acta obstetricia et gynecologica Scandinavica.

[14]  J. Martin,et al.  Three decades of twin births in the United States, 1980-2009. , 2012, NCHS data brief.

[15]  S. Bhattacharya,et al.  Global variations in the uptake of single embryo transfer. , 2011, Human reproduction update.

[16]  S. Bhattacharya,et al.  Clinical effectiveness of elective single versus double embryo transfer: meta-analysis of individual patient data from randomised trials , 2010, BMJ : British Medical Journal.

[17]  M. Fejgin,et al.  Nulliparity, fertility treatments and twins: a time for rethinking. , 2010, Fertility and sterility.

[18]  D. Young,et al.  Elective single embryo transfer following in vitro fertilization. , 2010, Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC.

[19]  D. Barad,et al.  Twin pregnancy, contrary to consensus, is a desirable outcome in infertility. , 2009, Fertility and sterility.

[20]  O. Erez,et al.  Primiparity, assisted reproduction, and preterm birth in twin pregnancies: a population based study , 2008, Archives of Gynecology and Obstetrics.

[21]  B. Sibai,et al.  Demographic and obstetric factors influencing pregnancy outcome in twin gestations. , 2002, American journal of obstetrics and gynecology.

[22]  G. Visser,et al.  Obstetric Outcome of Twin Pregnancies After In-Vitro Fertilization: A Matched Control Study in Four Dutch University Hospitals , 2001 .

[23]  B. Sibai,et al.  Hypertensive disorders in twin versus singleton gestations. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. , 2000, American journal of obstetrics and gynecology.