Drugs in pregnancy

Drug use during pregnancy can have temporary or permanent effects on the fetus. Any drug that acts during embryonic or fetal development to produce a permanent alteration of form or function is known as a teratogen. Drugs may refer to both pharmaceutical drug and recreational drugs.

Pharmaceutical drugs

The apprehension is not necessarily data driven and is a cautionary response to the lack of clinical studies in pregnant women. The indication is a trade-off between the adverse effects of the drug, the risks associated with intercurrent diseases and pregnancy complications, and the efficacy of the drug to prevent or ameliorate such risks. In some cases, the use of drugs in pregnancy carries benefits that outweigh the risks. For example, high fever is harmful for the fetus in the early months, thus the use of paracetamol (acetaminophen) is generally associated with lower risk than the fever itself. Similarly, diabetes mellitus during pregnancy may need intensive therapy with insulin to prevent complications to mother and baby. Pain management for the mother is another important area where an evaluation of the benefits and risks is needed. NSAIDs such as Ibuprofen and Naproxen are probably safe for use for a short period of time, 48–72 hours, once the mother has reached the second trimester.^[1] If taking aspirin for pain management the mother should never take a dose higher than 100 mg.^[1]

Pregnancy categories

U.S. Code of Federal Regulations requires that certain drugs and biological products must be labelled very specifically with respect to their effects on pregnant populations, including a definition of a "pregnancy category." These rules are enforced by the Food and Drug Administration (FDA).^[2][3] The FDA does not regulate labeling for all hazardous and non-hazardous substances and some potentially hazardous substances are not assigned a pregnancy category.

Anticonvulsants

Valproic acid, and its derivatives such as sodium valproate and divalproex sodium, causes cognitive deficit in the child, with an increased dose causing decreased intelligence quotient.^[4] On the other hand, evidence is conflicting for carbamazepine regarding any increased risk of congenital physical anomalies or neurodevelopmental disorders by intrauterine exposure.^[4] Similarly, children exposed lamotrigine or phenytoin in the womb do not seem to differ in their skills compared to those who were exposed to carbamazepine.^[4]

Alcohol

Medical organizations strongly discourage drinking alcohol during pregnancy.^[5][6][7] Alcohol passes easily from the mother's bloodstream through the placenta and into the bloodstream of the fetus,^[8] which interferes with brain and organ development.^[9] Alcohol can affect the fetus at any stage during pregnancy, but the level of risk depends on the amount and frequency of alcohol consumed.^[9] Regular heavy drinking and binge drinking (four or more drinks on any one occasion) pose the greatest risk for harm, but lesser amounts can cause problems as well.^[9] There is no known safe amount or safe time to drink during pregnancy.^[10]

Prenatal alcohol exposure can lead to fetal alcohol spectrum disorders (FASDs). The most severe form of FASD is fetal alcohol syndrome (FAS).^[10] Problems associated with FASD include facial anomalies, low birth weight, stunted growth, small head size, delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers.^[11][12] Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and develop substance use disorders themselves.^[11]

Recreational drugs

Recreational drug use during pregnancy can cause various pregnancy complications.

Cannabis

Cannabis in pregnancy is the subject of various scientific studies, usually regarding whether it has effects on the child later in life.

Smoking

A number of studies have shown that tobacco use is a significant factor in miscarriages among pregnant smokers, and that it contributes to a number of other threats to the health of the fetus.^[13][14] Smoking and pregnancy, combined, cause twice the risk of premature rupture of membranes, placental abruption and placenta previa.^[15] Also, it causes 30% higher odds of the baby being born prematurely.^[16]

Others

• Prenatal cocaine exposure is associated with, for example, premature birth, birth defects and attention deficit disorder.
• Prenatal methamphetamine exposure can cause premature birth and congenital abnormalities.^[17] Other investigations have revealed short-term neonatal outcomes to include small deficits in infant neurobehavioral function and growth restriction when compared to control infants.^[18] Also, prenatal methamphetamine use is believed to have long-term effects in terms of brain development, which may last for many years.^[17]
• Marijuana can cause low birth weight, tremors, poor eyesight, late start of breathing, and a hole in the heart. In the first six months of life babies who have been exposed to marijuana have a higher chance of having breathing problems such as asthma, chest infections, and wheezing. By the age of three or four the child might be fearful, reckless, inattentive, restless, irresponsible, and may have poor memory, verbal, and reasoning ability; at age ten these problems can continue along with depression, anxiety, reading and spelling problems.^[19]

By pregnancy stage

Pregnancy and fetal development progress through various changes. The period of one week from fertilisation to implantation of the fertilized egg is called the preimplantation period. This is an 'all or none' period, .i.e. an insult can either cause death or complete recovery can occur. The period from the eighth day to the end of eighth week is the period of organogenesis during which the organs are formed in the fetus. This is the most crucial time with regards to 'structural malformations' and concern over teratogenicity of drugs. From the third month to the end of nine months is the period of fetal maturation. Intake of drugs during this period may modify the 'function' of the fetal organs rather than causing gross structural malformations in the fetus; for example, aminoglycosides can affect the functioning of the kidneys as well as the hearing mechanism.

References

1. Kim, Joong; Segal, Neil (2015). Pharmacological Treatment of Musculoskeletal Conditions During Pregnancy and Lactation. Springer International Publishing. pp. 227–242. ISBN 978-3-319-14318-7.
2. FDA (1 Apr 2015), CFR - Code of Federal Regulations Title 21 4, Food and Drug Administration
3. FDA (3 Dec 2014), Pregnancy and Lactation Labeling (Drugs) Final Rule, Food and Drug Administration
4. Bromley, Rebecca; Weston, Jennifer; Adab, Naghme; Greenhalgh, Janette; Sanniti, Anna; McKay, Andrew J; Tudur Smith, Catrin; Marson, Anthony G; Bromley, Rebecca (2014). "Cochrane Database of Systematic Reviews". doi:10.1002/14651858.CD010236.pub2. |chapter= ignored (help)
5. Vice Admiral Richard H. Carmona (2005). "A 2005 Message to Women from the U.S. Surgeon General" (PDF). Retrieved 12 June 2015.
6. Committee to Study Fetal Alcohol Syndrome, Division of Biobehavioral Sciences and Mental Disorders, Institute of Medicine (1995). Fetal alcohol syndrome : diagnosis, epidemiology, prevention, and treatment. Washington, D.C.: National Academy Press. ISBN 0-309-05292-0.
7. "Australian Government National Health and Medical Research Council". Retrieved 4 November 2012.
8. Nathanson, Vivienne; Nicky Jayesinghe; George Roycroft (Oct 27, 2007). "Is it all right for women to drink small amounts of alcohol in pregnancy? No". BMJ 335 (7625): 857. doi:10.1136/bmj.39356.489340.AD. PMC 2043444. PMID 17962287.
9. "Fetal Alcohol Exposure". April 2015. Retrieved 10 June 2015.
10. "Facts about FASDs". April 16, 2015. Retrieved 10 June 2015.
11. Coriale; et al. (2013). "Fetal Alcohol Spectrum Disorder (FASD): neurobehavioral profile, indications for diagnosis and treatment.". Rivista di psichiatria 48 (5): 359–69. doi:10.1708/1356.15062. PMID 24326748.
12. Chudley; et al. (2005), "Fetal alcohol spectrum disorder: Canadian guidelines for diagnosis", CMAJ 172 (5 Suppl): S1–S21, doi:10.1503/cmaj.1040302, PMC 557121, PMID 15738468, retrieved 16 Apr 16 Check date values in: |access-date= (help)
13. Ness RB, Grisso JA, Hirschinger N; et al. (February 1999). "Cocaine and tobacco use and the risk of spontaneous abortion". N. Engl. J. Med. 340 (5): 333–9. doi:10.1056/NEJM199902043400501. PMID 9929522.
14. Oncken C, Kranzler H, O'Malley P, Gendreau P, Campbell WA; Kranzler; O'Malley; Gendreau; Campbell (May 2002). "The effect of cigarette smoking on fetal heart rate characteristics". Obstet Gynecol 99 (5 Pt 1): 751–5. doi:10.1016/S0029-7844(02)01948-8. PMID 11978283.
15. "Preventing Smoking and Exposure to Secondhand Smoke Before, During, and After Pregnancy" (PDF). Centers for Disease Control and Prevention. 2007.
16. "Tobacco Use and Pregnancy: Home". Centers for Disease Control and Prevention. 2009.
17. "New Mother Fact Sheet: Methamphetamine Use During Pregnancy" (PDF). North Dakota Department of Health. Archived (PDF) from the original on 2013-03-15. Retrieved 4 February 2014.
18. Grotta, S.; LaGasse, L.; Arria, A.; Derauf, C.; Grant, P.; Smith, L.M.; et al. (30 June 2009). "Patterns of Methamphetamine Use During Pregnancy: Results from the IDEAL Study". Matern Child Health J 14 (4): 519–527. doi:10.1007/s10995-009-0491-0. PMC 2895902. PMID 19565330.
19. University of Washington Alcohol & Drug Abuse Institute. "Marijuana". Reproduction and Pregnancy. Retrieved 2011.