Medically Assisted Reproduction (MAR)
The use of Medically Assisted Reproduction (MAR) is increasing globally due to a variety of reasons, including genetic factors, other health conditions as well as delayed childbearing and age-related fertility loss. Assisted Reproductive Technologies (ART) are technologies to support singles and couples with the conception of a child in case of infertility or genetic predispositions. Examples of ART include In-Vitro Fertilisation (IVF) or Intracytoplasmic Sperm Injection (ICSI), procedures in which egg cells are fertilised with sperm cells outside the human body. 
Preterm birth and pregnancy complications related to ART
Despite the undisputed benefits, the use of ART also bears some risks. The most common treatment-related adverse outcome is multiple pregnancy, which is mainly due to the transfer of multiple embryos. Multiple pregnancy is associated with increased neonatal and maternal risks, and research shows that preterm birth and foetal growth restriction are common complications in multiple pregnancy.  However, also among singleton births, ART bears an increased risk of preterm birth (delivery before 37 completed weeks of gestation) and birth defects. [3, 4, 5, 6] Singleton IVF pregnancies can furthermore be associated with increased risk of stillbirths, intrauterine growth restriction and admissions to the Neonatal Intensive Care Unit (NICU). [1, 7]
The reasons for increased preterm birth and other adverse outcomes in ART are not yet finally clarified. Studies show that one reason might be embryo manipulation, i.e. embryo culture and freezing/thawing procedures and endometrial transfer itself, which can lead to abnormal development of the placenta and attachment of the foetus to the uterus during pregnancy.  The associated complications could also reflect the underlying reason why ART was required to achieve a pregnancy in the first place, e.g. a history of infertility with or without assisted conception. [3, 6, 9]
Finally, infertility treatment may involve psychological health risks for the individuals involved, especially regarding the procedure itself and also in terms of handling adverse treatment outcomes.
FIGO recommendations regarding preterm birth and ART
The International Federation of Gynaecology and Obstetrics (FIGO) has formulated recommendations to reduce preterm birth in pregnancies conceived by ART: 
- ART and singleton IVF are associated with an increased risk for preterm birth and other pregnancy complications and could reflect the underlying reasons for infertility. This information should be discussed and contrasted with spontaneous conception.
- Before IVF is started, other approaches, including expectant management and other less invasive treatments, should be considered.
- In treatment with IVF, single embryo transfer (SET) is the best approach to prevent multiple pregnancy, which is unequivocally associated with preterm birth, and subsequent preterm birth, thus maximising the chance of having a healthy child.
- Embryo manipulation during cell culture should be minimised as it may impair implantation or the ability to maintain pregnancy and influence neonatal outcome.
- Mol BW et al. FIGO good practice recommendations on reduction of preterm birth in pregnancies conceived by assisted reproductive technologies. International Journal of Gynecology & Obstetrics. 2021 Oct;155(1):13-5.
- Kadir RA et al. Assisted Reproductive Technology and Multiple Pregnancy. InUltrasound in Assisted Reproduction and Early Pregnancy 2020 Oct 22 (pp. 190-197). CRC Press.
- Bu Z et al. Preterm birth in assisted reproductive technology: an analysis of more than 20,000 singleton newborns. Frontiers in Endocrinology. 2020;11.
- Dunietz GL et al. Assisted reproductive technology and the risk of preterm birth among primiparas. Fertility and sterility. 2015 Apr 1;103(4):974-9.
- Hansen M et al. Assisted reproductive technology and birth defects: a systematic review and meta-analysis. Human reproduction update. 2013 Jul 1;19(4):330-53.
- Davies MJ et al. Reproductive technologies and the risk of birth defects. New England Journal of Medicine. 2012 May 10;366(19):1803-13.
- Helmerhorst FM et al. Perinatal outcome of singletons and twins after assisted conception: a systematic review of controlled studies. Bmj. 2004 Jan 29;328(7434):261.
- Ernstad EG et al. Neonatal and maternal outcome after blastocyst transfer: a population-based registry study. American journal of obstetrics and gynecology. 2016 Mar 1;214(3):378-e1.
- Zhu JL et al. Infertility, infertility treatment, and congenital malformations: Danish national birth cohort. Bmj. 2006 Sep 28;333(7570):679.