University of Louisville School of Public Health and Information Sciences researcher Kira Taylor and her team analyzed data from more than 400 women for up to 19 months. The women completed daily diaries reporting how much alcohol they drank and what type.

Heavy drinking was defined as more than six alcoholic drinks a week, moderate drinking was three to six drinks a week, and binge drinking was defined as four or more drinks on a single day. A drink was defined as a third of a liter of beer, a medium glass of wine or just under a double shot of spirits. The researchers collected information on factors that could affect the results, such as age, medical history, smoking, obesity, intercourse frequency, use of birth control methods and intention to become pregnant.

“We found that heavy drinking during any phase of the menstrual cycle was significantly associated with a reduced probability of conception compared to non-drinkers,” Taylor said. “This is important because some women who are trying to conceive might believe it is ‘safe’ to drink during certain parts of the menstrual cycle.”

The research also found during the luteal phase, or the last two weeks of the menstrual cycle before bleeding starts and when the process of implantation occurs, not only heavy drinking but also moderate drinking was significantly associated with a reduced probability of conception. At the time of ovulation, usually around day 14 of the cycle, consuming a lot of alcohol – either heavy or binge drinking – was significantly associated with reduced chances of conception.

“If we assume that a typical, healthy, non-drinking woman in the general population who is trying to conceive has approximately a 25% chance of conceiving during one menstrual cycle, then out of 100 women approximately 25 non-drinkers would conceive in a particular cycle, about 20 moderate drinkers would conceive and only about 11 heavy drinkers would conceive,” Taylor said. “But the effect of moderate drinking during the luteal phase is more pronounced and only about 16 moderate drinkers would conceive.

“Our study only included a few hundred women and, while we believe the results strongly suggest that heavy and even moderate alcohol intake affects the ability to conceive, the exact percentages and numbers should be viewed as rough estimates,” she said.

Each extra day of binge drinking was associated with an approximate 19% reduction in the odds of conceiving during the luteal phase and a 41% reduction during the ovulatory phase. The researchers found no difference in their results between different types of drinks. The influence of drinking by male partners was not assessed.

While the study does not show that drinking alcohol causes the reduction in the chances of becoming pregnant, it does point to an association. Possible biological mechanisms to explain the association could be that alcohol intake affects the processes involved in ovulation so that no egg is released during the ovulatory part of the cycle, and alcohol could affect the ability of a fertilized egg to implant in the womb.

“The results in this study should not be construed to mean that drinking alcohol prevents pregnancy. In other words, alcohol is not birth control. Even if a woman drinks alcohol heavily, if she has unprotected intercourse, she can become pregnant,” Taylor said.

Economists Jacob Burgdorf and Conor Lennon from UofL and Keith Teltser at Georgia State University looked at data from 2009, when Uber was introduced, through 2016, and included UberX’s arrival in 2012.��Their paper signals total alcohol consumption and binge drinking both have risen in the period measured.

“Uber is naturally interesting because it’s this new thing; Jacob has research on beer distributors – he’s a beer industry guy – and I have co-authored a paper with Keith on bourbon and secondary markets for bourbon,” Lennon said, “so we have research on the alcohol industry, so naturally we were curious how does alcohol affect this (ride-sharing) industry.”

According to the research, it was determined that Uber has a larger effect on drinking in areas where public transportation is limited, noting a 17.5-to-21.8% increase in instances of binge drinking in those locales.

The findings also showed that Uber’s arrival coincides with an increase in average drinks, including a 4.9% rise in drinks on a single occasion and a 9% increase in incidences of heavy drinking.

“We were kind of surprised that nobody had focused exactly on this thing; everybody was focused on this secondary thing, which is drunk driving, which is after the fact,” Lennon said. “You have to make sure they’re not drinking more and drinking to excess and causing harm in other ways.

“Nobody had measured the first step.”

Burgdorf, Lennon, and Teltser also used their findings to investigate Uber’s impact on full-service restaurants, on the premise the ride-sharing app would have a positive effect on earnings at establishments serving alcohol. However, they found no significant impact on revenue, further suggesting that Uber is associated with increased consumption at “drinking places” and not full-service restaurants.

“If you go to Uber’s website, it says they’re strongly against drunk driving, and they have these free rides for people who are drunk, but they proudly announce that their busiest times are right around bar-closing time across the country,” Lennon said.

“… If Uber is announcing that, that’s almost telling you what Uber’s role is. It’s smacking you right in the face; the shocking thing is nobody wrote this paper before.”

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