Solvents: pregnancy outcome and fertility

1
Solvents pregnancy outcome and fertility

• Marja-Liisa Lindbohm
• Finnish Institute of Occupational Health

2
Organic solvents

• one of the most important occupational
  reproductive hazards
• widely used in various fields of industry
• volatile liquids
• absorbed via inhalation and through the skin
• most solvents traverse the placenta

3
Reproductive effects of solvents

• teratogenic, embryotoxic and behavioral effects
  in animal tests on mammals
• in several human studies exposure related to
• adverse pregnancy outcome and reduced fertility
• in some studies exposure related also to
• menstrual disorders and reduced hormone levels
• reduced semen quality
• pregnancy-induced hypertension
• neurobehavioral performance
• childhood cancer

4
Industries / individual solvents related to
reduced fertility or adverse pregnancy outcome

• Dry cleaning / tetrachloroethylene
• Shoe and leather industry / aliphatic
  hydrocarbons, toluene, hexane
• Semiconductor industry / ethylene glycol ethers
• Laboratory work / toluene, xylene, chloroform

5
Maternal exposure to tetrachloroethylene in dry
cleaning and spontaneous abortion
6
Spontaneous abortion, subfertility and maternal
exposure to ethylene glycol ethers in
semiconductor industry (Correa et al. 1996)
7
Results of studies among women working in the
shoe and leather industry

• indications of an increased risk of perinatal
  death, stillbirth, and oral clefts in children of
  shoe and leather workers (likely exposed to
  solvents)
• increased risk of spontaneous abortion and
  decreased fertility among shoe workers exposed to
  solvents (aliphatic hydrocarbons, toluene,
  hexane, acetone)

8
Cumulative percentage of pregnancies by maternal
exposure to solvents (Sallmén et al 1995)
9
Maternal exposure to solvents and birth defects

• McMartin et al. 1998
• meta-analysis of five studies (n7036)
• summary OR1.64 (95 CI 1.16 - 2.30)
• Solvent exposure linked with
• central nervous system defects, oral clefts,
  gastroschisis, ventricular septal defects,
  urinary tract defects

10
Conclusions Effects of solvent exposure on the
reproductive health of women

• High exposure to solvents increases the risk of
  spontaneous abortion and decreases fertility
• The findings on birth defects less conclusive,
  but suggesting adverse effects
• Particular solvents associated with adverse
  outcome ethylene glycol ethers,
  tetrachloro-ethylene, toluene

11
Exposure to solvents and semen quality or hormone
levels

• 2-bromopropane reduced sperm count
• Ethylene glycol ethers reduced sperm count
• Styrene and acetone sperm anomalies
• Toluene decrease of gonadotropin hormone levels
• Trichloroethylene hyperzoospermia
• Solvents low active sperm count and decreased
  implantation rate

12
Cumulative percentage of pregnancies by paternal
exposure to solvents (Sallmén et al. 1998)
13
Conclusions Effects of solvent exposure on the
reproductive health of men

• Ethylene glycol ethers harmful for male
  reproductive system
• Carbon disulfide related to decreased libido and
  potency in men
• No clear association between solvent exposure and
  decreased fertility
• Evidence on the effects of paternal exposure on
  pregnancy outcome inconclusive, although
  suggestive associations noted

14
Hazard assessment

• Exposure may be high for example in spray
  painting, shoe making, degreasing, printing and
  dry cleaning
• Assessment of solvent exposure with industrial
  hygienic measurements or biological monitoring
• In some countries the guidelines recommend that
  solvent exposure should not exceed 10 of the
  threshold limit value during pregnancy

15
References on solvent exposure and reproductive
health

• McMartin KI, Chu M, Kopecky E, Einarson TR, Koren
  G. Pregnancy outcome following maternal organic
  solvent exposure a meta-analysis of
  epidemiologic studies. Am J Ind Med
  199834288-292.
• Tas S, Lauwerys R, Lison D. Occupational hazards
  for the male reproductive system. Crit Rev
  Toxicol 199626261-307.
• Lindbohm M-L. Effects of parental exposure to
  solvents on pregnancy outcome. J Occup Environ
  Med 199537908-914.