Story highlights Couple writes anonymously about their frustration in being pregnant with twins after IVF

Online commenters call them selfish, bitter and ungrateful

Multiple births is common after IVF, but doctors are becoming more cautious

They struggled to get pregnant for nearly two years. They gave it a go the natural way and then did three or four intrauterine inseminations, where the sperm is washed, concentrated and placed directly into a woman's uterus at an optimal time.

But as mom and dad were both "pushing 40," these methods didn't work, and the couple decided to try in vitro fertilization. With in vitro, or IVF, several eggs are fertilized outside the body; the resulting embryos are then implanted in the woman's womb.

It worked -- on the first try. But the result wasn't exactly what this couple was looking for.

"To say we're excited would be an exaggeration," the dad wrote on Babble.com in an anonymous post that recently started trending on social media. "More truthfully, we're pissed. And terrified, and angry, and guilty, and regretful."

You see, both embryos that were implanted stuck. The wife is pregnant with twins.

"I lay on the table -- dazed and unhappy -- as I received the news that there were two healthy sacs present," the anonymous mom wrote in a separate post . "We were pregnant with twins -- twin boys, we'd find out later. In my mind I had done nothing less than ruin our family."

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To say the reaction from Babble's readers was angry would be an understatement. Many blasted the couple for being ungrateful. Selfish. Bitter. "Seriously, suck. it. up," one commenter wrote.

But there was a small majority who seemed to sympathize with how these new parents were feeling: overwhelmed, exhausted and afraid they won't be able to provide for these new lives in addition to their older son.

Multiple births are an increasingly common outcome for couples using assisted reproductive technology, according to the American College of Obstetricians and Gynecologists, and IVF is often responsible.

"A woman undergoing IVF has an approximate 22-fold increased risk of conceiving a twin pregnancy and a 100-fold increased risk of conceiving a triplet pregnancy, as compared with natural conception," ACOG's website says

So why do doctors still occasionally place multiple embryos in women who undergo IVF? Because the chances that even one will stick and grow into a baby are low. According to the Society for Assisted Reproductive Technologies , women under the age of 35 have a less than 43% chance of giving birth after IVF; women over 41 have a less than 18% chance.

Dr. Dorothy Mitchell-Leef, a fertility specialist in Atlanta, always has a long conversation with her patients before implanting any embryos. She said she discusses the risks, the possibility of multiples and the chances that the couple may not get pregnant.

"They may be angry because maybe that's not what they wanted," Mitchell-Leef said of the anonymous couple on Babble.com. "But they have to ask themselves: Did you have a conversation that stressed the fact that you did not want more than one pregnancy?"

The problem, she said, is that no doctor can promise which embryos are going to take, if any at all.

IVF specialists have become more cautious. As doctors saw the multiple birth rates increase dramatically in the United States, they began transferring fewer embryos to the mother. Most of the time, Mitchell-Leef said, she only implants one. But the quality of the embryos matters; so does the woman's age.

A 41-year-old with three embryos has a low chance of any one of those being normal, "but the better chance is to put three in hoping that one will take," Mitchell-Leef said.

You may remember how Nadya Suleman -- aka "Octomom" -- was criticized for not reducing the number of embryos she carried before giving birth to octuplets.

Selective reduction -- which involves aborting one, or more than one, of the fetuses -- was also a possibility for this anonymous Babble couple. In general, the decision to do a reduction for twins is extremely controversial. Twins don't necessarily carry high health risks to the mother or her children beyond perhaps needing bed rest and more intense care, Mitchell-Leef said.

"We considered a reduction for about 30 seconds," this anonymous father wrote. "If you thought that IVF involved playing god, a reduction felt beyond brazen -- Machiavellian, even."

Selective reduction is usually done between 9 and 12 weeks into the pregnancy. A doctor will use a needle to inject potassium chloride into the fetus, according to the National Institutes of Health . There is a small risk the mother will miscarry all the fetuses with this procedure.

Multiple gestation is risky for both mom and the babies, according to the American Society for Reproductive Medicine. Multiples are more likely to have developmental problems. Moms carrying multiples are more likely to miscarry, develop gestational diabetes and to suffer from high blood pressure-related issues such as pre-eclampsia.

But multiples can also be a blessing.

"You will make it work and you will love these children," posted one commenter, who says she's the mother of twins. "I won't lie and say that it is going to be a breeze, because it won't. But I promise you if you pull through the first year together as a team you will be the strongest kind of family there can be, and nothing can stop you from there!"