Zoloft and Breastfeeding: What the Evidence Shows

Summary: Overall, taking Zoloft while breastfeeding is not recommended. While blood levels of Zoloft and it’s metabolite are relatively low in the baby – some higher levels have popped up. The long term effects of drugs like Zoloft on a baby’s development are not known at this time. A natural step any mother can take to lower the risk of Postpartum Depression is to increase the amount of omega 3 fatty acids she eats and/or consider supplementing.

Dear Curtis: After my first baby I suffered with some Postpartum Depression. I have heard that Zoloft doesn’t build up as much in the breast milk and may be a good option for me as I want to breastfeed exclusively. Is Zoloft safe during breastfeeding for my baby and me?

This is always a tough question to answer because whenever it comes to taking any medication during pregnancy and breastfeeding we aren’t relying on long-term, big scale studies. In fact, health care professionals often have to rely on sometimes sketchy feedback from case studies because there are obvious ethical concerns about studying any drug in an unborn fetus or newborn baby.

In this situation what I like to do is give you the basic evidence we have at this point. You can bring this to your doctor and make a good decision for both you and the baby. I’ll also encourage you to look at some other options as well. But more on that in a second.

Zoloft Levels In Breast Milk

One of the things you mentioned right off the bat was that you interested in Zoloft because it doesn’t build up as much in the breast milk.

That’s not entirely true.

While most case studies have shown very low or no levels of detectable Zoloft in the babies blood after breastfeeding, one study in 1998 – which looked at 9 breastfed infants – showed different results. While the actual levels of Zoloft in the babies blood was low (<2ng/mL can’t be quantified by the lab and the highest level recorded was 3 ng/mL), the levels of the metabolite of Zoloft showed some odd fluctuations.

For example, in the infants the blood levels of Zoloft’s metabolite ranged from not measurable to 24 ng/mL (the mothers metabolite levels ranged from 28-285 ng/mL). But the ninth infants metabolite levels jumped up to 64 ng/mL – which was nearly 60% of the mother’s blood level. This alarmed the researchers enough that they thought they had made a mistake and remeasured the babies blood levels. Same thing and no rationale explanation as to why it jumped so much in one baby.

The next question becomes does the metabolite of Zoloft (called desmethylsertraline) have any effects in the baby?

As far as we know, the metabolite of Zoloft is relatively inactive. However, as far as what are the long-term effects of the metabolite and Zoloft? No one really knows.

Bottom Line on Zoloft and Breastfeeding

When it comes down to it, some of the effects and side effects of Zoloft are well known. But we really don’t know the long-term effects of Zoloft or it’s metabolite on the behavior and development of the babies who have been exposed to it.

If you want to paint with a broad brush stroke, it’s probably fair to say that in most cases Zoloft doesn’t appear to show up in the babies blood at very high levels (although it does show up). But how high of a level are you and your doctor willing to roll the dice with?

In short, most doctors are going to tread very lightly when it comes to giving any antidepressant to a mother who is breastfeeding. And, if you want a recommendation from the baby experts – the American Academy of Pediatrics – they consider Zoloft a drug for which the effects on breast-fed infants is unknown – but may be of concern.

Other Options

The question really becomes what is the risk to your baby? We’ve all heard of the unfortunate stories of Mom’s who’ve suffered from bad postpartum depression which, left untreated, turned out bad.

So, what’s riskier – to not treat with an antidepressant or to roll the dice on the unknown effects on the baby? Only you and your doctor can come up with the answer to that. But, rather than thinking that this is an either or situation I’d like to suggest some other options as well.

  • Nutrition:let’s face it. People who eat poorly are deficient in a lot of nutrients. One of the most interesting ones when it comes to depression is the Omega-3 fatty acids. You can increase your food intake of these or also consider supplementing. This is not only safe for you, but for your baby as well.Also, there is evidence that mothers low in Omega 3 fatty acids (compared to Omega 6 fatty acids) run a higher chance of developing Postpartum Depression. I’d really encourage you to talk to your doctor about supplementing as well as changing how you eat.Here are some reviews of a good, solid and relatively inexpensive Omega 3 supplement.
  • Time Your Feeding Sessions:you’ll hear different numbers, but as a whole, Zoloft appears to peak in the blood about four hours after it’s dosed. So, perhaps avoiding feeding during those peak hours might help. However, one thin that is overlooked is the basic chemistry of Zoloft.First of all, it takes a long time for your body to eliminate Zoloft. Secondly, Zoloft is more basic (higher pH). Breast milk is more acidic (lower pH). This can actually ‘trap’ the Zoloft in the milk. So I’m not too sure how effective this strategy will be overall. But it might be worth a shot.It’s also important for you to understand that Zoloft (and other drugs in it’s class) can actually slow down lactation because of it’s effects on serotonin balance in your body. So, you might find breastfeeding more difficult.
  • Don’t Breastfeed: OK – it’s sounds like this option is out for you as you want to breastfeed exclusively. But, it is something that needs to be considered especially if the risk to you and the baby from postpartum depression is high.

I do want to leave you with one more thing and it’s the recommendation from the Brigg’s Breast Feeding Recommendation. Overall, this is what most medical professionals turn to when they need a definitive source on whether or not something should be given during pregnancy or breastfeeding.

In the exact words of the Briggs manual:

“No (Limited) Human Data – Potential Toxicity. Either there is no human data or the human data are limited. The characteristics of the drug suggest that it could represent a clinically significant risk to a nursing infant. Breastfeeding is not recommended.”


Wisner KL, Perel JM, Blumer J. Serum sertraline and N-desmethylsertraline levels in breastfeeding mother-infant pairs. Am J Psychiatry 1998;155:690–2.

da Rocha CM, Kac G. High dietary ratio of omega-6 to omega-3 polyunsaturated acids during pregnancy and prevalence of post-partum depression. Matern Child Nutr. 2012 Jan;8(1):36-48. doi: 10.1111/j.1740-8709.2010.00256.x. Epub 2010 Jun 21