Women defy biology to avoid giving birth on Halloween

Nerdy AND cute...as long as he wasn't actually born on Oct. 31.

So, it’s October and Halloween is just a few weeks away! You’re thinking about costume ideas, maybe planning a party and, oh yeah, you’re doing your darndest not to give birth on the creepiest day of the year, a holiday that some say celebrates paganism.

“But wait, what does Halloween Day have to do with giving birth? Or any day, for that matter? Don’t women just have babies when the time comes?” Well, apparently not, because, according to researchers at Yale, women can and do choose to avoid bringing their babies into the world concurrently with the “Festival of the Dead.”

I’m not just talking C-sections — the phenomenon inexplicably holds true for C-sections and spontaneous births. And Halloween isn’t the only holiday that has women strongly influencing their birth timing, either. This research ultimately leaves me with more questions than answers, but sometimes that’s the best kind of science.

Cute :)

Ah, Valentine’s Day, a sweet day of love, right? Even if you’re woefully single, you can at least imagine the love that a mother has for her child, which certainly has a positive connotation. Flowers, cards, and candy also don’t hurt this day’s reputation.

But Halloween? Sure, it’s fun from ages 3-13 (and then again after 21…), but on some level, you can’t help but worry about whether your house is going to get egged or toilet papered. And despite the candy, let’s be honest — witches and death are not inherently warm and fuzzy concepts.

Sinister...? :(

So, going on the logic that Valentine’s Day has a positive cultural representation and   Halloween has a negative one, these scientists set out to see whether the perceptions of these days could influence births — even spontaneous births, which have been considered beyond a pregnant woman’s control. [The benefit of studying these days is that they have strong cultural participation, but doctors are generally present at work; this is in contrast to, say, Christmas, where the connotations might be positive, but doctors are on vacation.]

Using 10-years’ worth of U.S. birth certificate data provided by the National Center for Health Statistics, the researchers focused on the two-week period spanning Valentine’s Day and Halloween. The results are straight-forward and don’t need much preamble:

Natural and C-section births jumped significantly on Valentine’s Day, with the overall increased likelihood of giving birth being calculated at 5% for the day of love.

Halloween, on the other hand? Different story:

All types of births — natural, C-section, induced — decreased significantly on All Hallows’ Eve. Overall, a whopping 11.3% decrease in births was seen on this day across the years. That’s a pretty clear indicator that women don’t want their babies associated with hauntings and horror.

Okay, so the numbers are definitive. But how could women exert control over when they give birth?! The short answer is that no one has any idea. The closest that these authors come to suggesting a psychophysiological mechanism is to say that wanting to give birth on Valentine’s Day and resisting giving birth on Halloween could, for a short time, alter the hormonal mechanisms responsible for determining birth timing.

More work needs to be done to understand the biology of how this is happening and I, for one, can’t wait to see what comes of this area of study.


Levy BR, Chung PH, & Slade MD (2011). Influence of Valentine’s Day and Halloween on Birth Timing. Social science & medicine (1982), 73 (8), 1246-8 PMID: 21880409

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23 Responses to Women defy biology to avoid giving birth on Halloween

  1. daedalus2u says:

    The mechanism for both days is the same, the effects of hormones on the birth process. High stress suppresses birth, low stress facilitates birth. If a predator is around, that is a bad time to give birth and birth will be delayed (to some extent), but that delay is not unlimited. That is why there was a catch-up excess the next day.

    Stress is a low NO state. NO is what causes smooth muscle to relax. The uterous is smooth muscle. For the cervix to dilate, there must be enough NO so the muscles can relax enough. Too much stress and birth can’t happen so easily. That is why the catch-up was in c-sections. If a woman is in labor for “too long”, they will do a c-section. If she went into labor on Halloween and didn’t give birth, she gets a c-section the next day.

    The other hormone that affects the uterus is oxytocin. Oxytocin makes the uterus contract. Oxytocin is also the hormone that triggers (and is triggered by) pair bonding. If you are in a long term relationship with a mate, your oxytocin level will be higher on days traditionally devoted to such things, like Valentine’s day.

    There are probably all sorts of reminders of Valentine’s day in an obstetric ward, and the lovey-dovey feelings of Valentine’s day probably have an effect on women in labor.

    • NerdyOne says:

      I agreed with the authors that the hormonal makeup would be at play in this, but I was still very shocked by the to-the-day specificity of it! Your suggestions fit perfectly with the observations, and I’m still in awe that the female body could have such tightly timed regulation of these events. Thanks! :)

  2. charlie says:

    interesting! I found a slightly more mundane phenomenon related to the holidays while playing with Google Trends. By searching for food items, you can find various holidays: “pumpkin” shows spikes at halloween, thanksgiving, and christmas. “potato” spikes at thanksgiving and christmas, with smaller peaks at easter and fourth of july. Interestingly, nutritional information takes a sharp dip during the winter holidays; both “protein” and “starch” bottom out over november-december.

    I’ll leave it as an exercise to the reader to explain what happens with “sex” :)

    • NerdyOne says:

      Haha! I’m sure there are patterns with sex too, although I’m still amazed about the one-day specificity of birth timing…. Thanks for the input!

  3. Katie says:

    Interesting! My husband was born 3 days before Halloween, so Halloween is his favorite holiday and personal obsession. So I tend to think of Halloween-ish birthdays positively, but I see why a lot of mom’s wouldn’t.

    • NerdyOne says:

      Haha, that’s awesome that you find positivity where many see negativity! It’d be interesting to study individual women and their feelings about their due date, and whether there were any “coincidences” that lined up with their feelings!

  4. I’ve always suspected that the human mind (or subconsious) has a lot more control over biology than is normally believed and this is an interesting confirmation of that. As someone who enjoys Halloween (to me, a holiday that is just for fun without family obligations) I’m amazed that so many people have such negative and/or superstitious feelinga about it.

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  7. Amy says:

    Or…maybe Valentine’s Day gives a feeling of being pampered and cared for, a day of rest, but Halloween is associated with work… dressing up the older sibling, making cupcakes for the daycare party, buying and handing out treats to the neighborhood children.

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  9. thorton says:

    Women aren’t avoiding Halloween, they’re holding out for Day of the Dead.

  10. Coach Holiday says:

    My wife was born on Valentines Day and her father was born on Halloween. Put that in your pipe.

  11. I was induced with my eldest daughter at 7 am on October 30. She held out until 3:11 on the 31st to please her father, a St. Patrick’s Day baby. How many other people have midwives who are late to the hospital because they were rear ended by Snow White? It’s fun to have a Halloween baby!

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  13. Jessica says:

    Someone sent me this link because I’m due on Oct. 30. People have been telling me all along how fun Halloween birthdays are, how their friend who had a Halloween birthday always had the best parties, etc. I wouldn’t mind if she came on Halloween!

  14. Karen says:

    I was born on Halloween and I love it! When I was little I thought everyone was dressing up to celebrate my birthday! I was crushed to find out this wasn’t the case! LOL

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